Registration Dossier
Registration Dossier
Data platform availability banner - registered substances factsheets
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Diss Factsheets
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 217-533-1 | CAS number: 1879-09-0
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Repeated dose toxicity: oral
Administrative data
- Endpoint:
- short-term repeated dose toxicity: oral
- Remarks:
- combined repeated dose and reproduction / developmental screening
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- Not specified
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
Cross-reference
- Reason / purpose for cross-reference:
- reference to same study
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 1 993
Materials and methods
Test guidelineopen allclose all
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- other: “The order for specifying the items for the study on new chemical substances, and the investigation on the designated chemical substances. Article 4: Test Facility,” Kankiken No. 233, Eisei No. 38, 63 Kikyoku No. 823 (November 18, 1988).
- Deviations:
- no
- GLP compliance:
- not specified
- Limit test:
- no
Test material
- Reference substance name:
- 6-tert-butyl-2,4-xylenol
- EC Number:
- 217-533-1
- EC Name:
- 6-tert-butyl-2,4-xylenol
- Cas Number:
- 1879-09-0
- Molecular formula:
- C12H18O
- IUPAC Name:
- 2-tert-butyl-4,6-dimethylphenol
- Test material form:
- liquid: viscous
- Details on test material:
- Name of the test substance: 6-tert-butyl-2, 4-xylenol
CAS No.: 1879-09-0
Code N0.: B0903
Purity: 98.5%
Storage conditions: room temperature, in the dark
Storage place: archive for test substance, in BioSafety Research Center
Chemical name: 6-tert-butyl-2, 4-xylenol
Molecular formula: (CH3)3CC6H2(CH3)2OH
Molecular weight: 178.27
Description: liquid
Color: very pale yellow, transparent
Solidification point: 21.5°C
Solubility: water-insoluble
Specific gravity (d20/20): 0.9612
Refractive index (n20/D): 1.5186
Precaution for handling: Appropriate eye protective device, protective gloves and protective mask were worn during handling. Hand washing and sufficient gargle were performed after handling.
Storage of test substance and Disposal of the residue: After the end of administration, about 2 g of test substance was stored in BioSafety Research Center, and the remainder was discarded.
Constituent 1
- Specific details on test material used for the study:
- No further details specified in the study report.
Test animals
- Species:
- rat
- Strain:
- Crj: CD(SD)
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- Test animals: Seventy males and 70 females of Crj:CD(SD) strain rats (SPF) were purchased from Japan Charles River Co., Ltd., (Atsugi-shi, Kanagawa) at 8-weeks of age on September 20, 1993, quarantined and acclimatized to the test environment for 7 days. 48 males and 48 females which showed no abnormalities in general condition during the acclimatization period were allocated to each group after 8 days of preliminary housing period at 10-weeks of age.
At the end of grouping, the males weighed 339-400 g and the females weighed 226-265 g.
Animal husbandry: The animals were housed in an animal room (W 5.7 x D 10.0 x H 2.5 m, 142.5m3) kept by barrier system under the target environmental conditions at 22-26°C of temperature, 45-65 % of relative humidity with 15 times per hour of ventilation frequency, and 12 hour lighting of 150-300 lux (lighting at 7: 00 am and turn off at 7:00 pm).
Animals were housed individually in a cage with aluminum front and stainless steel mesh-floor (W 15.8 x D 23.8 x H 16.0 cm, Space: 6017 cm3). Cages were set on a water-flush breeding instrument (W 691.0 x D 79.0 x H 195.0 cm) supplied by Tokyo Giken Service Co. Ltd. (Fuchu-shi, Tokyo). However, during the mating period, males were housed in cages with aluminum front and stainless steel mesh-floor (W 36.8 x D 25.0 x H 16.0 cm, Space: 14720 cm3). Dam after 18 days of gestation was housed in a cage with aluminum front and stainless steel mesh-floor (W 36.8 x D 25.0 x H 16.0 cm) with a lactation tray and nesting materials (Alpha-dry) until day 4 of lactation. The cages were exchanged once every other week, and food suppliers were exchanged once a week.
The food used was NMF solid food (treated with radiation sterilization) supplied by Oriental Yeast Co., Ltd. (Chuo-ku, Tokyo). The food was available ad libitum. The analysis of contaminant in the food used in this study was conducted in Japan Food Research Laboratories (Shibuya-ku, Tokyo) on the request by Oriental Yeast Co., Ltd.
The animals were allowed free access to drinking water of tap water. The analyses of tap water were performed 4 times in a year in Examination Center of Life Science of Shizuoka (Hamamatsu-shi, Shizuoka). The food, water and nesting material supplied did not contain any contaminants which were considered to have affected the results of the study.
There were no environmental deviations which might have affected the reliability of the study data during the duration of housing period.
Test groups: Animals were stratified by the body weights and allocated to each test group by randomization method on October 5, 1993.
Animals were identified by ear-punch and attaching animal identification card with animal identification number (animal ID-No.) to cages. Before grouping, animals were identified by tentative animal numbers.
The remained animals were euthanized by carbon dioxide.
Administration / exposure
- Route of administration:
- oral: gavage
- Vehicle:
- corn oil
- Details on oral exposure:
- Oral rout of administration was selected according to the indication described in OECD Guideline “Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Study”.
Administration volume was 0.5 ml per 100g of body weight, and the administration volume was calculated based on the most recent individual body weight. The test substance was administered by gavage once a day (7 days/week) using a stomach tube. Control animals were treated with corn oil only in an identical manner.
Male animals were administered for 45 days consecutively from 14 days before mating, during 14 days of mating period and up to 17 days after the end of mating period. Female animals were administered from 14 days before mating, during mating period (until the day of copulation confirmation, 14 days at the longest), gestation period after copulation and up to day 3 of lactation after delivery (41-48 days). Infertile female animal was administered for 44 days until the day before necropsy (day 25 of gestation). - Analytical verification of doses or concentrations:
- yes
- Details on analytical verification of doses or concentrations:
- The analysis of homogeneity and concentration of the dosing preparation was conducted on the sample taken randomly from batches of each group prepared at the start of administration. As shown in Reference data 5, mean values of the concentration in each preparation were within 99.3-104 %, and the coefficient of variation was lower than 0.8 % indicating that the preparations were properly adjuste
- Duration of treatment / exposure:
- Male animals were administered for 45 days consecutively from 14 days before mating, during 14 days of mating period and up to 17 days after the end of mating period. Female animals were administered from 14 days before mating, during mating period (until the day of copulation confirmation, 14 days at the longest), gestation period after copulation and up to day 3 of lactation after delivery (41-48 days). Infertile female animal was administered for 44 days until the day before necropsy (day 25 of gestation).
- Frequency of treatment:
- The test substance was administered by gavage once a day (7 days/week) using a stomach tube.
Doses / concentrations
- Remarks:
- Doses / Concentrations:
0, 6, 30, 150 mg/kg
Basis:
actual ingested
- No. of animals per sex per dose:
- 12 animals per dose group.
- Control animals:
- yes, concurrent vehicle
- Details on study design:
- Reason for selection of the species: The use of rat is indicated by OECD Guideline. The species was selected considering the stability in estrus cycle, reproduction and genetic.
Reasons for the selection of dose levels: Dose levels were selected by considering the results of “Combined Repeated Dose Toxicity with the Reproduction/Developmental Toxicity Preliminary Study in Rats” (study number 2265) conducted previously. In this preliminary study, dose levels of 0, 75, 150, 300 and 600 mg/kg were administered to males and females for 14 consecutive days, and all animals treated with 600 mg/kg died. Suppression in body weight gain was seen in male groups treated with 300 mg/kg or more and in females treated with 600 mg/kg. Decrease in food intake was seen in male groups treated with 150 mg/kg or more, and females treated with 300 mg/kg or more.
Among the organ weight at necropsy, both absolute and relative weights of liver increased in male groups treated with 75 mg/kg or more, and in female groups treated with 150 mg/kg or more.
At necropsy, enlargement of liver was seen in males treated with 150 or 300 mg/kg and females treated with 300 mg/kg.
From the above results and taking into account of the longer administration period in the main study, 150 mg/kg was selected as the highest dose level. The lower dose levels of 30 and 6 mg/kg were selected by dividing the highest dose level by common geometric ratio of 5. - Positive control:
- Positive control not utilised in this study.
Examinations
- Observations and examinations performed and frequency:
- Male animals
Clinical observations: All animals were observed with the frequency of once or more in a day during the study period.
Body weight: All animals were weighed on days 0 (start of administration), 7, 14, 21, 28, 35, 42 and 45 (day of necropsy). In addition, the body weight gain during the study period was calculated.
Measurement of food intake: Food given to all animals were weighed on days 0 (start of administration), 7, 14, 21, 28, 35, 42 and 44 (day before necropsy), and mean daily food intake was calculated by the amount on the measurement day and the amount on the next measurement day. In addition, cumulative food intake during the administration period was calculated. Food intake during mating period when males were housed together with females was not measured.
Hematology: All animals were fasted for about 16 hours from the evening of the last day of administration period (45 days) to the next morning, and then blood samples were obtained from the abdominal aorta under ether anesthesia. Blood samples obtained at the first bleeding were used for the examination. Blood samples were collected into sample cups containing anticoagulant (EDTA-3K) and examined on the items listed below using a total hematological examination system THMS H 6000 (Technicon Corporation, USA).
Hematocrit (HCT): Calculated from total volume of erythrocytes
Hemoglobin(HGB): Cyanmethemoglobin method
Erythrocyte count (RBC): Dark field plate method
Mean corpuscular volume (MCV): Calculated from RBC and HCT
Mean corpuscular hemoglobin (MCH): Calculated from HGB and RBC
Mean corpuscular hemoglobin concentration (MCHC): Calculated from HGB and HCT
Platelet count (PLT): Dark field plate method
Leukocyte count (WBC): Dark field plate method
Differential leukocyte count: Flow cytometry
Differential leukocyte counts were determined with the instrument described above. However, blood smear was prepared and stained with May-Grunwald-Giemsa stain and stored.
Reticulocyte (RC) counts were determined by the microscopic observation of blood smear stained with a glass capillary tube for reticulocyte staining (Terumo Corporation, Shibuya-ku, Tokyo).
Blood chemistry: At the same time of the sampling for the hematological examination, blood samples were obtained from the abdominal aorta and put into vessels, Clean Seal (Yatron Corporation, Chiyoda-ku, Tokyo). The samples were centrifuged at 3000 rpm for 7 minutes after being left for 30 minutes, and serum was obtained and used for the analysis. Parameters indicated below were assayed using Multi-item biochemistry auto-analyzer, CentrifiChem ENCORE II (Baker Corporation, USA) and EKTACHEM 700N (Kodak Corporation, USA).
Total protein (T. protein): Burette method
Albumin (Albumin): B.C.G. method
A/G (A/G): Calculation
Glucose (Glucose): Glucose oxidase method
Urea nitrogen (BUN): Modified urease method
Creatinine (Creatinine): Jaffé method
Total bilirubin (T. Bilirubin): Diazo colorimetric analysis
Glutamic oxaloacetic transaminase (GOT): Modified Karmen method
Glutamic pyrubic transaminase (GPT): Modified Karmen method
γ-Glutamyltranspeptidase (Gamma-GTP): Modified Szasz method
Potassium (Potassium): Electrode method
Chloride (Chloride): Electrode method
Calcium (Calcium): Arsenazo III method
Inorganic phosphate (I. Phosphate): Ammonium molybdate method
Female animals
Clinical observations: All animals were observed with the frequency of once or more in a day during the study period.
Body weight: All animals were weighed on days 0 (start of administration), 7, 14 and 21. After copulation, animals were weighed on days 0, 7, 14 and 21 of gestation, and on days 0 and 4 of lactation after delivery. In addition, body weight gain during the administration period was calculated.
Measurement of food intake: Food given to all animals were weighed on days 0 (start of administration), 7 and 14, and on days 0 and 4 of lactation after delivery, and mean daily food intake was calculated by the amount on the measurement day and the amount on the next measurement day. In addition, cumulative food intake during the administration period was calculated. - Sacrifice and pathology:
- Male animals
Necropsy and organ weight: Macroscopic observations of organs and tissues were performed on the animals euthanized by exsanguinations after blood sampling. Thymus, liver, kidney, testis and epididymides were weighed, and the ratio of organ weight to body weight (relative weight) was calculated. In addition, thymus, liver, kidney, brain, heart, spleen, adrenals, seminal vesicles, prostate, pituitary and the tissues with abnormal findings (lung, mass in the abdominal cavity) of all animals were fixed in 10% neutral buffered formaldehyde solution. The testis and the epididymides were fixed in Bouin solution.
Histopathology: Paraffin sections from the fixed organs and tissues indicated below were prepared by Histo Science Laboratory Co., Ltd., (Oume-shi, Tokyo) and routinely stained with hematoxylin-eosin. In addition, kidney was stained with PAS reaction. Microscopic observations were conducted in BioSafety Research Center.
Fertile male: Brain, thymus, heart, liver, kidney, spleen, adrenals, testis of all animals of the control group and 150 mg/kg group and the tissues with abnormal findings in all groups. Thymus, liver, kidney and adrenals of all animals of 6 and 30 mg/kg groups.
Infertile male: Brain, thymus, heart, liver, kidney, spleen, adrenals, testis, epididymides, seminal vesicles, prostate and pituitary.
Female animals
Necropsy and organ weight: The animals necropsied are shown below and the presence of abnormalities in the organs and tissues was observed.
Dead animal: Animals were necropsied immediately after found dead. Skin, mammary glands, lymph nodes, salivary glands, sternum, femoral bone (with bone marrow), thymus, trachea, lung with bronchus, heart, thyroids with parathyroid glands, tongue, esophagus, stomach, duodenum, small intestine, large intestine, liver, pancreas, spleen, kidney, adrenals, urinary bladder, ovaries, uterus, vagina, eyes, Harderian glands, brain, pituitary and spinal cord were fixed in 10% neutral buffered formaldehyde solution.
Female with natural delivery: Animals were euthanized by exsanguination under ether anesthesia on day 4 of lactation, and main organs were observed macroscopically. And then, thymus, liver, kidney and ovaries were weighed, and the ratio of organ weight to body weight (relative weight) was calculated. In addition, thymus, liver, kidney, ovaries, brain, heart, spleen, adrenals, pituitary and the tissues with abnormal findings of all animals were fixed in 10% neutral buffered formaldehyde solution.
Female without natural delivery: On day 25 of gestation, animals were euthanized by exsanguinations under ether anesthesia, and macroscopic observations of main organs were performed. Skin, mammary glands, lymph nodes, salivary glands, sternum, femoral bone (with bone marrow), thymus, trachea, lung with bronchus, heart, thyroids with parathyroid glands, tongue, esophagus, stomach, duodenum, small intestine, large intestine, liver, pancreas, spleen, kidney, adrenals, urinary bladder, ovaries, uterus, vagina, eyes, Harderian glands, brain, pituitary and spinal cord were fixed in 10% neutral buffered formaldehyde solution. Animal with no implantation sites was judged to be infertile.
Female whose pups all died: On the day or the next day when the death or cannibalism of pups were found, parental females were euthanized by exsanguinations under ether anesthesia, and macroscopic observations of main organs were performed. Skin, mammary glands, lymph nodes, salivary glands, sternum, femoral bone (with bone marrow), thymus, trachea, lung with bronchus, heart, thyroids with parathyroid glands, tongue, esophagus, stomach, duodenum, small intestine, large intestine, liver, pancreas, spleen, kidney, adrenals, urinary bladder, ovaries, uterus, vagina, eyes, Harderian glands, brain, pituitary and spinal cord were fixed in 10% neutral buffered formaldehyde solution. The numbers of corpora lutea of pregnancy and implantation sites were examined at the necropsy.
Histopathology: Paraffin sections from the fixed organs and tissues indicated below were prepared by Histo Science Laboratory Co., Ltd., (Oume-shi, Tokyo) and routinely stained with hematoxylin-eosin. In addition, kidney were stained with PAS reaction. Microscopic observations were conducted in BioSafety Research Center.
Dead animal: Skin, mammary glands, lymph nodes, salivary glands, sternum, femoral bone (with bone marrow), thymus, trachea, lung with bronchus, heart, thyroids with parathyroid glands, tongue, esophagus, stomach, duodenum, small intestine, large intestine, liver, pancreas, spleen, kidney, adrenals, urinary bladder, ovaries, uterus, vagina, eyes, Harderian glands, brain, pituitary and spinal cord.
Female with natural delivery: Brain, thymus, heart, liver, kidney, spleen, adrenals, ovaries of all animals of the control group and 150 mg/kg group, and the tissues with abnormal findings of all animals of all groups. Thymus, liver, kidney and adrenals of all animals of 6 mg/kg group and 30 mg/kg group.
Infertile female: Brain, thymus, heart, liver, kidney, spleen, adrenals, vagina, ovaries and pituitary.
Female whose pups all died: Skin, mammary glands, lymph nodes, salivary glands, sternum, femoral bone (with bone marrow), thymus, trachea, lung with bronchus, heart, thyroids with parathyroid glands, tongue, esophagus, stomach, duodenum, small intestine, large intestine, liver, pancreas, spleen, kidney, adrenals, urinary bladder, ovaries, uterus, vagina, eyes, Harderian glands, brain, pituitary and spinal cord. - Other examinations:
- Observations and examinations on the reproduction of parental animals and neonates was also performed as part of the reproduction/developmental toxicity study.
- Statistics:
- Data of this study were recorded using a computer system, and the results of the study were statistically analyzed using the following methods.
The mean value per dam was used as one sample for the results of neonates during lactation period. Levels of significance were two steps of * : P < 0.05 and ** : P < 0.01.
Multiple comparison analysis was applied for body weight, food intake, number of corpora lutea of pregnancy, implantation site, number of birth, number of still birth, sex ratio, mean value of estrus cycle duration, gestation period, implantation index, delivery index, live birth index, incidence of external anomaly, viability index on day 4 of neonates, organ weight, ratio of organ weight to body weight (relative organ weight), hematology and blood chemistry.
First, the homogeneity was assessed by Bartlett test. If homogeneity was obtained, one way analysis of variance was applied. If variance was significant and the numbers of samples were equal among groups, Dunnett multiple comparison was applied. In the case of unequal numbers of samples, the significances of difference between the control group and each treated group were assessed by Scheffé multiple comparison.
When the data showed non-homogeneity by Bartlett test, the data were analyzed by Kruskal-Wallis rank sum test. Dunnett rank test was applied if significance was obtained and numbers of sample were equal, and in the case of unequal numbers of samples, Scheffé rank test was applied for the analysis of significant difference between the control group and each treated group.
Results and discussion
Results of examinations
- Clinical signs:
- effects observed, treatment-related
- Description (incidence and severity):
- Detailed in results
- Mortality:
- mortality observed, treatment-related
- Description (incidence):
- Detailed in results
- Body weight and weight changes:
- effects observed, treatment-related
- Description (incidence and severity):
- Detailed in results
- Food consumption and compound intake (if feeding study):
- no effects observed
- Description (incidence and severity):
- Higher mean values of daily food intake were seen in 150 mg/kg group from day 28 to 35 of administration compared to the control group. However, cumulative food intake showed no differences between these groups.
- Food efficiency:
- not examined
- Water consumption and compound intake (if drinking water study):
- not examined
- Ophthalmological findings:
- not examined
- Haematological findings:
- effects observed, treatment-related
- Description (incidence and severity):
- Deatiled in results
- Clinical biochemistry findings:
- effects observed, treatment-related
- Description (incidence and severity):
- Detailed in results
- Urinalysis findings:
- not examined
- Behaviour (functional findings):
- no effects observed
- Organ weight findings including organ / body weight ratios:
- effects observed, treatment-related
- Description (incidence and severity):
- Detailed in results
- Gross pathological findings:
- effects observed, treatment-related
- Description (incidence and severity):
- Detailed in results
- Histopathological findings: non-neoplastic:
- effects observed, treatment-related
- Description (incidence and severity):
- Detailed in results
- Histopathological findings: neoplastic:
- not examined
- Details on results:
- Effect on male animals
Mortality and clinical observation: There was no death during the administration period.
In clinical observations, alopecia (fore limb) in a rat of 6 mg/kg group, eye discharge in 2 rats of 30 mg/kg group, urogenital hemorrhage in a rat of 150 mg/kg group, and teeth abnormality (broken incisive tooth of upper jaw) in 1, 2 and 1 rats were observed in the control, 30 mg/kg and 150 mg/kg groups, respectively.
Body weight: No differences between the control group and test substance administered groups were seen.
Food intake: Higher mean values of daily food intake were seen in 150 mg/kg group from day 28 to 35 of administration compared to the control group. However, cumulative food intake showed no differences between these groups. No differences from that in the control group were seen in 6 mg/kg and 30 mg/kg groups.
Hematology: Compared to the control group, hematocrit value, hemoglobin concentration and erythrocyte count were lower, and reticulocyte count was higher in 150 mg/kg group. Reticulocyte count was also higher in 6 mg/kg group. In addition, percentage of lymphocytes was low and the ratio of neutrophils was high in 150 mg/kg group, but these changes were slight. Erythrocyte count in 6 mg/kg group and leukocyte count in 30 mg/kg group showed higher values. However, the changes were not dose dependent.
Blood chemistry: Chloride level was higher and potassium level was lower in all of test substance administered groups compared to the control group. In 30 and 150 mg/kg groups, levels of total protein, albumin and γ-GTP were higher and GOT level was lower than compared to the control group. In addition potassium level showed low level in 150 mg/kg group. High inorganic phosphate level was seen in 30 mg/kg group, but this was not dose dependent change.
Organ weight: Compared to the control group, relative weight of liver was higher in 30 mg/kg group, and relative and absolute weights of liver and kidney were higher in 150 mg/kg group. No differences from the control group were seen in organ weight of 6 mg/kg group.
Macroscopic findings
Fertile male: Macroscopic finding often observed in the groups treated with test substance was enlargement of liver which was seen in 1 and 9 rats of 30 mg/kg group and 150 mg/kg group, respectively. Other changes considered to be spontaneous occurrence were colored patch/zone (brown) in lung, deformed liver (abnormal lobulation), mass in the abdominal cavity (fat necrosis), cyst and scar in kidney, atrophy of testis and epididymis were sporadically seen in 30 mg/kg group and 150 mg/kg, and yellowish liver was seen 2 control animals.
Infertile male: One infertile male was noted in the control group and no abnormalities were observed in this animal.
Histopathology
Fertile male: The finding with apparently higher incidence in 150 mg/kg group compared to the control group was hypertrophy of centrilobular hepatocytes (Photo. 2) which were seen in 9 animals out of 12 animals. In addition, the incidence of vacuolation of adrenal glands was slightly higher in the test substance administered groups compared to the control group. The other findings showed no differences in the incidence between the control group and test substance administered groups. Thymus, liver, kidney and adrenals were examined in 6 mg/kg group and 30 mg/kg group and no abnormalities were observed in liver or kidney.
Infertile male: One infertile male was noted the control group. Pigmentation in the spleen, fatty change of hepatocytes and basophilic change of tubules, and vacuolation of adrenal glands were observed in the infertile animal.
Effect on female animals
Mortality and clinical observation: Two females died on day 23 of gestation in 150 mg/kg group. Decrease in locomotor activity was seen on the day before death in one animal (animal No. 2302). The other animal (animal No. 2305) died during delivery. No deaths were seen throughout the administration period in the other administration groups.
In the clinical observation, eye discharge was seen in one female of 30 mg/kg group, alopecia (fore limb, hind limb, neck) was seen in one control animal and 2 animals in 6 mg/kg group.
Body weight: Lower body weight gain compared to the control group was seen in 150 mg/kg group from day 0 to day 21 of gestation. No differences were seen in 6 mg/kg group and 30 mg/kg group compared to the control group.
Food intake: No differences between the control group and test substance administered group were seen throughout the administration period.
Organ weight: Compared to the control group, relative organ weights of liver and kidney were higher in 150 mg/kg group, and absolute weights of these organs showed tendency of high values. No differences were seen in 6 and 30 mg/kg groups compared to the control group.
Macroscopic findings
Dead animal: Two animals died in 150 mg/kg group. Enlargement of liver was seen in 2 animals. Reddish lung, yellowish small intestine, white patch/zone in liver and enlargement of kidney and adrenals were observed in one animal.
Female sacrificed on day 4 of lactation: The findings often observed in the groups treated with test substance were as follows. Atrophy of thymus was observed in one rat in 6 mg/kg group, 2 rats in 30 mg/kg group and one rat in 150 mg/kg group. White patch/zone in liver and enlargement of adrenal glands were observed in 2 animals each in 150 mg/kg group. Pale kidney was seen in one female each in 6 and 150 mg/kg groups. Sporadic findings observed in test substance administered groups were red patch/zone in thymus, colored patch/zone (yellowish) in small intestine, anomaly nodule in liver (hyperplasia), pale or red liver, dilatation of pelvis and enlargement of kidney and thinning of hair.
Infertile female: Infertile female was seen in one rat in the control group. No abnormalities were observed in the animal.
Female whose pups all died: Females whose pups all died until day 4 of lactation were one in 30 mg/kg group and 3 in 150 mg/kg group. Enlargement of liver was seen 3 females (all animals) and red patch/zone was seen in 2 females in 150 mg/kg group. Sporadic changes observed were scar in heart, colored patch/zone in thymus (brown), black patch/zone and a nodule in lung, white patch/zone in stomach, white small intestine, white liver, black kidney, enlarged and pale kidney and enlargement of adrenal glands.
Histopathology
Dead animal: Two animals died in 150 mg/kg group. Pigment deposition in spleen, thickening of tunica media of blood vessels in lung, parakeratosis in tongue and esophagus, hyaline droplet degeneration, centrilobular necrosis, single cell necrosis and centrilobular hypertrophy of hepatocytes in liver, hyaline droplet degeneration, granular proteinaceous casts in kidney and hyperplasia in the mammary gland were seen in both 2 animals.
Female sacrificed on day 4 of lactation: The finding with apparently higher incidence in 150 mg/kg group than in the control group was hypertrophy of centrilobular hepatocytes. In addition, the incidence of atrophy of thymus was slightly higher in the test substance administered groups. Findings observed in several animals in 150 mg/kg group but not in the control group were necrosis of centrilobular hepatocytes and granuloma in liver, deposition of PAS positive granules at the papilla of kidney, and granular proteinaceous casts and necrosis of the proximal convoluted tubules. Other observed findings showed no differences in the incidence between the control group and test substance administered groups.
In 6 mg/kg group and 150 mg/kg group, thymus, liver, kidney and adrenal glands were examined. There were no abnormalities in liver and kidney. However, the incidence of thymus atrophy was similar to that in 150 mg/kg group.
Infertile female: Infertile female was seen one in the control group. In this animal, cell infiltration in heart, pigment deposition in spleen and granulation foci in liver were observed.
Female whose pups all died: Females whose pups all died were seen one in 30 mg/kg group and 3 in 150 mg/kg group. In all of these animals, atrophy of thymus, pigment deposition in spleen, parakeratosis in tongue and fatty change of liver were observed. In addition, hemorrhage in lung, parakeratosis in esophagus, mitosis of hepatocytes, centrilobular necrosis of hepatocytes, single cell necrosis of hepatocytes, hypertrophy of hepatocytes, proteinaceous casts, basophilic change of tubules, mitosis, dilatation of tubules, necrosis and vacuolation of proximal convoluted tubules in kidney were observed in 2 or 3 animals out of 3 animals treated with 150 mg/kg.
Effect levels
open allclose all
- Key result
- Dose descriptor:
- NOEL
- Effect level:
- 6 mg/kg bw/day (actual dose received)
- Based on:
- test mat.
- Sex:
- male
- Basis for effect level:
- other: overall effects clinical signs; mortality; body weight; food consumption; haematology; clinical chemistry; gross pathology; organ weights; histopathology;
- Key result
- Dose descriptor:
- NOEL
- Effect level:
- 30 mg/kg bw/day (actual dose received)
- Based on:
- test mat.
- Sex:
- female
- Basis for effect level:
- other: overall effects clinical signs; mortality; body weight; food consumption; haematology; clinical chemistry; gross pathology; organ weights; histopathology
Target system / organ toxicity
- Critical effects observed:
- not specified
Any other information on results incl. tables
This report was translated from the original Japanese report. The translated copy is appended below for reference.
Applicant's summary and conclusion
- Conclusions:
- Based on the results, no observed effect level (NOEL) was estimated to be 6 mg/kg in male and 30 mg/kg in female.
- Executive summary:
In order to evaluate the toxicological nature of existing chemical substances, the repeated dose toxicity as well as the effect on reproduction and development were studied by the administration of 6-tert-butyl-2, 4-xylenol at the dose levels of 0 (vehicle control), 6, 30 and 150 mg/kg/day to rats for the period from 14 days before mating, during mating period, gestation period and to day 3 of lactation.
The general toxicological effect as well as the effect on reproduction and development were studied following the OECD Guidelines for “Testing of Chemicals; Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Screening Test, Extended Steering Group Document No. 3” (March 22, 1990).
The conduct of the study was designed to fulfill the standard described in “The order for specifying the items for the study on new chemical substances, and the investigation on the designated chemical substances. Article 4: Test Facility,” Kankiken No. 233, Eisei No. 38, 63 Kikyoku No. 823 (November 18, 1988).
No effect of the test substance administration were seen in the general condition of animals, but 2 female rats treated with 150 mg/kg died in the last stage of gestation (one rat died during delivery). In the females of 150 mg/kg group, suppression in body weight gain was observed during gestation period, however, no effect of the administration of test substance were seen in the body weight of male and the food intake of male and female rats.
In the hematological examination, low values in hematocrit, hemoglobin content and erythrocyte count were seen together with the high values in reticulocyte count and slight tendency of anemia in the male animal of 150 mg/kg group. In blood chemistry, low level of GOT and high level of γ-GTP were observed in 30 and 150 mg/kg groups.
Organ weights of liver and kidney were increased or showed a tendency to increase in male groups treated with 30 mg/kg or more and in female group treated with 150 mg/kg. In macroscopic observation, enlargement of liver was seen in male groups treated with 30 or 150 mg/kg, and enlargement of liver and kidney was observed in female group treated with 150 mg/kg. In the histopathology examination, the following findings were considered to be due to the test substance administration. Hypertrophy of centrilobular hepatocytes was observed in the male group treated with 150 mg/kg. Hypertrophy of centrilobular hepatocytes, degeneration of hepatocytes, necrosis of centrilobular hepatocytes and single cell necrosis in liver were seen in 150 mg/kg females at necrosis on day 4 of lactation. Parakeratosis in tongue and esophagus, hypertrophy of centrilobular hepatocytes as well as various degeneration, single cell necrosis and increase in mitotic figures in liver were observed in dead animals and the animals whose pups all died. In addition, degeneration of proximal convoluted tubules, proteinaceous casts and deposition of PAS positive granules at the papilla in kidney were observed in the female of this group.
From the results, repeated administration of 6-tert-butyl-2, 4-xylenol induced low level of GOT and high level of γ-GTP in the males of 30 and 150 mg/kg group, death and suppression of body weight gain, increase in organ weight and enlargement in liver and kidney in the females of 150 mg/kg group, anemic tendency, increase in organ weight of liver and kidney, and enlargement of liver in the male of 150 mg/kg group. In addition, by histopathology examination, abnormal findings were seen in liver of males and females, and in kidney of females in 150 mg/kg group. Thus, the target organs of the test substance were considered to be liver and kidney. Based on the results, no observed effect level (NOEL) was estimated to be 6 mg/kg in male and 30 mg/kg in female.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.