Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate

Specific investigations: other studies

Administrative data

Endpoint:

hepatotoxicity

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable study report which meets basic scientific principles

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1973

Report date:

1973

Materials and methods

Principles of method if other than guideline:

Groups of 8 rats (4/sex/group) received continuously the test substance in feed for 2 weeks at concentrations of 350, 700, 1400 and 2000 ppm. The animals were closely observed for the signs of toxicity. During week 2, ascorbic acid content was assayed in urine. On completion of the treatment period, all surviving rats were killed by cervical dislocation. The appearance of the tissues was then noted and the weights of brain and liver were recorded. Microscopic examination was carried out on livers from all rats. Liver microsomes were prepared and analyzed for Cytochrome P450, protein concentration and metabolism enzymes.

GLP compliance:

no

Type of method:

in vivo

Endpoint addressed:

acute toxicity: oral

Test material

Test material information

Constituent 1

Reference substance name:

Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate

EC Number:

218-216-0

EC Name:

Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate

Cas Number:

2082-79-3

Molecular formula:

C35H62O3

IUPAC Name:

octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate

Test animals

Species:

rat

Strain:

other: CFY

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Carworth Europe, Alconbury, England
- Weight at study initiation: 200-220 g
- Housing: 4/cage
- Diet (e.g. ad libitum): powdered laboratory rat food, Spratt's Laboratory Diet
- Water (e.g. ad libitum): tap water
- Acclimation period: 4-6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21±2
- Humidity (%): 50±5

Administration / exposure

Route of administration:

oral: feed

Details on exposure:

DIET PREPARATION
A pre-mix containing 5000ppm was prepared each week, and from this various dietary concentrations were obtained by direct dilution with further quantities of diet, homogeneity being achieved by mixing for 10 minutes in a rotary double-cone blender. The diets were then stored until use in heat-sealed, opaque polythene bags.

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

2 weeks

Frequency of treatment:

continously

Post exposure period:

none

Doses / concentrations

Remarks:

Doses / Concentrations:
350, 700, 1400 and 2000 ppm
Basis:
nominal in diet

No. of animals per sex per dose:

4

Control animals:

yes, concurrent no treatment

Examinations

Examinations:

DETAILED CLINICAL OBSERVATIONS: Yes

BODY WEIGHT: Yes
- Time schedule for examinations: initially and at termination

URINALYSIS: Yes
- Time schedule for collection of urine: during week 2
- Metabolism cages used for collection of urine: No data
- Animals fasted: No data
- Parameters checked: ascorbic acid

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes
On completion of the treatment period, all surviving rats were killed by cervical dislocation. The appearance of the tissues was then noted and the weights of brain and liver were recorded. For inter-group comparison, relative organ weights were calculated as percentages of brain weight. Samples of liver and brain were preserved in buffered 4% formaldehyde. Microscopic examination was carried out on livers from all rats.

Other examinations: Drug metabolising enzymes
- Preparation of rat-liver microsomes: Rats were killed by cervical dislocation, and samples of the livers were removed quickly into ice-cold buffered potassium chloride and homogenized in 5 volumes of buffered potassium chloride (1.15% w/v). The homogenates were centrifuged and the microsomal fractions were prepared by centrifugation of this supernatant.
- Estimation of Cytochrome P450: Cytochrome P450 was assayed by the method of Omura & Sato (Methods in Enzymology. 10, 556, 1967).
- Enzymic assays: Aniline hydroxylase, aminopyrine-N-demethylase and p-nitrobenzoic acid reductase were assayed.
- The protein concentration of the microsomal suspension used was also determined.

Positive control:

no

Results and discussion

Details on results:

CLINICAL SIGNS AND MORTALITY:
There were no overt signs of reaction to treatment. There were no mortalities during the treatment period.

BODY WEIGHT AND WEIGHT GAIN:
The gain in bodyweight of females receiving 1400 or 2000 ppm was lower than that of control females (P<0.01 and <0.05 respectively). The difference was not dosage related and was not recorded among males receiving the same dosage levels. The difference in bodyweight gain, among females receiving 1400 or 2000 ppm was, therefore, considered to be a fortuitous occurrence. Bodyweight gain of the other rats was comparable with that of the controls.

URINALYSIS:
The urinary excretion of ascorbic acid during 16 hours following administration of the test substance in the diet at 2000 ppm was significantly increased (P<0.05) over that of the controls.

ORGAN WEIGHTS:
In all dose groups, there was no significant difference in absolute liver weights, or in the relative liver weights expressed as a percentage of brain weight.

GROSS PATHOLOGY:
No treatment-related changes were recorded.

HISTOPATHOLOGY: NON-NEOPLASTIC:
Liver sections only were examined from all animals from each group. The hepatic architecture was within normal limits. Minimal variation in hepatocyte size and occasional small foci of mononuclear cell infiltration were seen in all groups. One rat (700 ppm) showed minimal bile duct reduplication confined to a small area of liver. Another rat (1400 ppm) showed a perilobular chronic inflammatory focus circumscribed by degenerate hepatocytes. No changes in morphology were seen which were considered to be related to treatment with the test compound.

Any other information on results incl. tables

OTHER FINDINGS Microsomal drug-metabolizing enzymes and cytochrome P450:

- Although increases in the activities of hepatic drug-metabolising enzymes usually occur with related increases in hepatic microsomal protein concentration, no significant increase in hepatic microsomal protein concentrations was detected after administration of the test article. Although increases in microsomal protein concentrations were recorded, they were small relative to the increases in the activities of the drug metabolising enzymes and were masked by the large animal variation recorded. - The results indicate a general increase in the activity of the microsomal enzymes, among animals fed test material at a dietary concentration of 1400 or 2000 ppm, although levels of significance were not obtained for all enzymes. The increases, however, paralleled the increase in cytochrome P450 concentrations, this relationship being more apparent among male rats. Concentrations of cytochrome P450 were significantly increased in male rats fed the test substance at a dietary concentration of 1400 ppm. Among treated females, although rats fed the test substance at a dietary concentration of 2000 ppm showed an elevation in cytochrome P450, the difference from control values did not achieve a level of significance. - Expressing the data in terms of microsomal protein content of the liver resulted in significant increases in enzyme activity in male and female rats for aniline hydroxylase (P<0.05 at 2000 ppm) and 9-nitroanisole-O-demethylase (P<0.05 at 2000 ppm). Significant increases in enzyme activity were detected in female rats for aminopyrine-N-demethylase (P<0.05 at 1400 or 2000 ppm).