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Diss Factsheets
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EC number: 200-795-6 | CAS number: 73-22-3
- 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
Carcinogenicity
Administrative data
Description of key information
Key value for chemical safety assessment
Carcinogenicity: via oral route
Link to relevant study records
- Endpoint:
- carcinogenicity: oral
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 1975 - 1978
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Acceptable, well documented publication/study report which meets basic scientific principles
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- OECD Guideline 451 (Carcinogenicity Studies)
- Deviations:
- yes
- Remarks:
- dosing only for 78 weeks, limited number of animals per group, some parameters such as haematology, clinical chemistry and urinalysis not examined
- GLP compliance:
- no
- Species:
- rat
- Strain:
- Fischer 344
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- Source: Charles River, Wilmington
Weight (g): ca. 70 – 90
Age (days): 30
Diet: ad libitum
Water: ad libitum
Pre-dose acclimatisation period: 12 d
Environmental conditions:
Temperature (°C): 22 ± 2
Relative humidity (%): 50 ± 10
Photoperiod (hrs dark / hrs light): 9 / 15
Air changes (per hr): 15 - Route of administration:
- oral: feed
- Vehicle:
- unchanged (no vehicle)
- Details on exposure:
- Test diets were prepared every 2 weeks by mixing a known amount of sifted L-tryptophan with a small amount of Wayne Lab Blox animal meal in a portable mixer, then adding this mixture to the required amount of animal meal and mixing in a twin-shell blender for 10 minutes.
- Analytical verification of doses or concentrations:
- no
- Duration of treatment / exposure:
- 78 weeks
- Frequency of treatment:
- continuously via diet on 5 days per week
- Post exposure period:
- 26-27 weeks
- Remarks:
- Doses / Concentrations:
0, 25000 or 50000 ppm (ca. 0, 1250 or 2500 mg/kg bw/d)
Basis:
nominal in diet - No. of animals per sex per dose:
- 35 animals/sex/dose and 15 animals/sex as controls
- Control animals:
- yes, plain diet
- Details on study design:
- Dose selection rationale: based on a range-finding study
- Positive control:
- no
- Observations and examinations performed and frequency:
- CLINICAL / CAGE SIDE OBSERVATIONS: yes (twice daily; palpations of the animals were carried out at each weighing)
BODY WEIGHT: yes (on day 0, thereafter every 2 weeks through week 86 and once every month until termination) - Sacrifice and pathology:
- Gross and microscopic examination of major tissues, major organs, and all gross lesions from killed animals and from animals found dead. The following tissues were examined microscopically: skin, muscle, lungs and bronchi, trachea, bone marrow, spleen, lymph nodes, thymus, heart, salivary gland, liver, gallbladder, pancreas, oesophagus, stomach, small intestine, large intestine, kidney, urinary bladder, pituitary, adrenal, thyroid, parathyroid, mammary gland, prostate or uterus, testis or ovary, brain, and sensory organs. Peripheral blood smears were prepared from each animal whenever possible. Occasionally, additional tissues were also examined microscopically. The different tissues were preserved in 10% buffered formalin, embedded in paraffin, sectioned, and stained with haematoxylin and eosin. Special staining techniques were utilized when indicated for more definitive diagnosis.
A few tissues from some animals were not examined, particularly from those animals that died early. Also, some animals were missing, cannibalized, or judged to be in such an advanced state of autolysis as to preclude histopathological evaluation. Thus, the number of animals from which particular organs or tissues were examined microscopically varies, and does not necessarily represent the number of animals that were placed on study in each group. - Other examinations:
- no
- Statistics:
- yes
- Clinical signs:
- no effects observed
- Mortality:
- no mortality observed
- Body weight and weight changes:
- no effects observed
- Description (incidence and severity):
- : differences in mean body weights among dosed and control groups were minimal (statistics not given)
- Food consumption and compound intake (if feeding study):
- not examined
- Food efficiency:
- not examined
- Water consumption and compound intake (if drinking water study):
- not examined
- Ophthalmological findings:
- not examined
- Haematological findings:
- not examined
- Clinical biochemistry findings:
- not specified
- Urinalysis findings:
- not examined
- Behaviour (functional findings):
- not examined
- Organ weight findings including organ / body weight ratios:
- not specified
- Gross pathological findings:
- no effects observed
- Histopathological findings: non-neoplastic:
- no effects observed
- Histopathological findings: neoplastic:
- no effects observed
- Dose descriptor:
- NOAEL
- Effect level:
- ca. 2 500 mg/kg bw/day
- Based on:
- test mat.
- Sex:
- male/female
- Remarks on result:
- other: Effect type: carcinogenicity (migrated information)
- Conclusions:
- A bioassay of L-tryptophan for possible carcinogenicity was conducted by administering the test chemical in feed to Fischer 344 rats. Groups of 35 rats of each sex were administered L-tryptophan at dose levels of 0, 25000 or 50000 ppm (ca. 0, 1250 or 2500 mg/kg bw/d) on 5 days per week for 78 weeks, and then observed for 26 or 27 weeks. Matched controls consisted of groups of 15 rats of each sex. All surviving rats were killed at 104 or 105 weeks. L-tryptophan had little toxic effect on the rats, as mean body weight loss was minimal and survival of dosed groups of both sexes was high. Sufficient numbers of rats were at risk to termination of the study for development of late-appearing tumours. No neoplasms occurred in a statistically significant incidence among dosed rats when compared to controls. It can be concluded that under the conditions of this bioassay, L-tryptophan was not carcinogenic for Fischer 344 rats.
Reference
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
- Dose descriptor:
- NOAEL
- 2 500 mg/kg bw/day
- Study duration:
- chronic
- Species:
- rat
Carcinogenicity: via inhalation route
Endpoint conclusion
- Endpoint conclusion:
- no study available
Carcinogenicity: via dermal route
Endpoint conclusion
- Endpoint conclusion:
- no study available
Justification for classification or non-classification
L-tryptophan was not carcinogenic in rats and mice under the conditions of the NCI study. No classification according to EU and GHS criteria is necassary.
Additional information
A bioassay of L-tryptophan for possible carcinogenicity was conducted by administering the test chemical in feed to Fischer 344 rats. Groups of 35 rats of each sex were administered L-tryptophan at dose levels of 0, 25000 or 50000 ppm (ca. 0, 1250 or 2500 mg/kg bw/d) on 5 days per week for 78 weeks, and then observed for 26 or 27 weeks. Matched controls consisted of groups of 15 rats of each sex. All surviving rats were killed at 104 or 105 weeks. L-tryptophan had little toxic effect on the rats, as mean body weight loss was minimal and survival of dosed groups of both sexes was high. Sufficient numbers of rats were at risk to termination of the study for development of late-appearing tumours. No neoplasms occurred in a statistically significant incidence among dosed rats when compared to controls. It can be concluded that under the conditions of this bioassay, L-tryptophan was not carcinogenic for Fischer 344 rats.
In a parallel study, groups of 35 B6C3F1 mice of each sex were dosed with 0, 25000 or 50000 ppm (ca. 0, 3750 or 7500 mg/kg bw/d) on 5 days per week for 78 weeks, and then observed for 26 weeks. Matched controls consisted of groups of 15 mice of each sex. All surviving mice were killed at 104 weeks. In both male and female mice, neoplasms of the hematopoietic system occurred at higher incidences in the low-dose groups than in the matched-control groups (males: controls 0/12, low-dose 9/34, high-dose 2/33; females: controls 2/13, low-dose 6/33, high-dose 1/35). These incidences, however, are not statistically significant and therefore, no tumors are considered to be related to the administration of the test chemical. It can be concluded that under the conditions of this bioassay, L-tryptophan was not carcinogenic for B6C3F1 mice.
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