Repeated Dose Oral Toxicity Study Research Articles

A case of spontaneous true hermaphroditism in the rat with evidence of female character.

Spontaneous true hermaphroditism in a rat is reported. This animal was a unilateral hermaphrodite composed of a testis on the left and an ovotestis on the right, although the external genitalia was masculine. In the present case, there were epididymides and vasa deferentia on both sides, an oviduct and a uterine horn on the right side, and seminal vesicles dorsal to the uterus, but prostate glands and the external orifice of vagina were absent. The ovotestis, unlike the other cases of hermaphroditic rats, was composed of a predominant ovarian tissue and a small area of testicular tissue. The present animal died by a single administration, i.e. the first administration in a repeated dose oral toxicity study, of a test compound having sex difference in the lethal toxicity. The dose given to the animal is expected to cause lethal effects in females but not in males, and the sex difference is presumed to depend on the different activity of S-oxidation by cytochrome P-450, the drug-metabolizing exzyme of the liver. These matters suggest that this animal had been enzymatically female.

A fifty two-week oral repeated dose toxicity study of suplatast tosilate (IPD-1151T) in dogs

A 52-week oral repeated dose toxicity study of suplatast tosilate (IPD-1151T), a newly developed anti-allergic agent, was carried out in beagles by oral administration of 30, 90, 270 and 810 mg/kg/day for 52 weeks. The recovery study was carried out by the withdrawal for 5 weeks using control and the 810 mg/kg groups. The results are as follows: 1. Observation of general conditions revealed soft feces, mucous feces, and diarrhea in both sexes of the 270 and 810 mg/kg groups during the administration period, and these findings disappeared during the withdrawal period. One female of the 810 mg/kg group exhibited tremors in the legs and neck, staggering, a decrease of spontaneous motor activity, and clonic convulsions in Week 17 of administration and died on Day 118. One male of the same group exhibited whole body tremors and staggering from Week 32 to Week 52. 2. Body weight gain tended to be inhibited in males of the 810 mg/kg group during the administration period. The body weight of the female that died decreased rapidly after the appearance of neurological symptoms. The body weight of the male that exhibited neurological symptoms decreased after their appearance but later increased. 3. There were no abnormal changes in food consumption in all of the sacrificed dogs. The female that died did not eat at all after the appearance of neurological symptoms. The male that exhibited neurological symptoms did not eat at all for 1 week after their appearance, but the food consumption returned to normal thereafter. 4. Prothrombin times were prolonged in males of the 270 and 810 mg/kg groups at Week 26, and activated partial thromboplastin times were prolonged in males of the 810 mg/kg group at Week 52. 5. Plasma levels of alkaline phosphatase, GPT and LDH were elevated in some males and females of the 810 mg/kg groups. 6. No abnormalities due to IPD-1151T administration were found in urinalysis, opthalmological examination, electrocardiography, and fecal occult blood examination, or organ weights. 7. Autopsies including histopathological and electron microscopic examinations on the sacrificed dogs revealed no abnormalities. Subserosal hemorrhage in the base of the heart, congestion in the lungs, congestion and vacuolation in the liver and slight cell infiltration around vessels of the brain were found in the female that died.(ABSTRACT TRUNCATED AT 400 WORDS)

A THIRTEEN-WEEK ORAL REPEATED DOSE TOXICITY STUDY OF SUPLATAST TOSILATE (IPD-1151T) IN RATS

A 13-week oral repeated dose toxicity study of Suplatast tosilate (IPD-1151T), a new anti-allergic agent, as well as a 5-week recovery study were carried out at dose levels of 0 (control), 200, 600, 1800 and 5400 mg/kg/day using male and female rats. The results were as follows: 1. In general conditions, salivation were observed in some rats of both sexes given 1800 mg/kg/day. Both sexes given 5400 mg/kg/day disclosed salivation and soft stool and then died after showing ataxic gait, hyperesthesia and convulsion of legs. 2. Inhibition of body weight gain in both sexes given 5400 mg/kg/day were observed from the early stage of the treatment period. 3. The food consumption was decreased from about 3-week and the water consumption was increased from the initiation of study to about 3-week in both sexes given 5400 mg/kg/day. However, both of them were remarkably decreased prior to death. 4. Fecal examination for occult blood showed an increasing tendency in the incidence of positive findings in both sexes given 1800 mg/kg/day. 5. Hematological examination showed slight decreases in erythrocytic parameters in both sexes given 1800 mg/kg/day. In both sexes given 5400 mg/kg/day hemoconcentration was observed, some animals showing decreases in leucocyte and lymphocyte counts and lymphocyte percentage. 6. Biochemical examination showed increases in total and free cholesterol levels in males given 600 mg/kg/day or more, an increased cholinesterase and decreased levels of triglyceride and cholesterol ester ratio in males given 1800 mg/kg/day. An increase in LDH was observed in both sexes given 5400 mg/kg/day and half of these animals also showed increases in GOT and Urea N. 7. The absolute weights of the pituitary, brain, thymus, heart, lungs and kidneys were increased. However, no histopathological lesion was observed in these organs. As treatment-related histological changes, atrophy in the thymus and spleen, dilation in digestive tracts, neuronal necrosis and necrotic foci in the central nervous system, necrosis of lymphocytes in the lymphoid organs and a decrease in bone marrow cell were observed in both sexes given 5400 mg/kg/day. 8. After a 5-week recovery period, above-mentioned changes had disappeared. 9. From the above results, the non-effective dose level was estimated to be 200 mg/kg/day in males and 600 mg/kg/day in females, and toxic dose level 1800-5400 mg/kg/day in both sexes.

A fifty-two week oral chronic toxicity study of suplatast tosilate (IPD-1151T) in rats

A 52-week oral repeated dose toxicity study of suplatast tosilate (IPD-1151T), a new anti-allergic agent, as well as a 5-week recovery study were carried out at dose levels of 0 (control), 50, 300 and 1800 mg/kg/day using male and female rats. The results were as follows: 1. In general conditions, transient salivation after each administration and excretions with peculiar smells were noted in both sexes given 1800 mg/kg/day. Since one male and six female rats given 1800 mg/kg/day showed bradypnea, clonic/tonic convulsions, lying on the belly and/or side, subnormal temperature, abnormal gait, paralysis of extremities, they were sacrificed in moribund. 2. The body weight was lowered from the early stage of administration period in both sexes given 1800 mg/kg/day. 3. There were no remarkable changes in food consumption, urinalysis, fecal examination, hematology and ophthalmology. 4. Biochemical examination revealed a decrease in triglyceride in males given 300 mg/kg/day or more. 5. In pathological examination, the animals sacrificed in moribund showed necrosis and degeneration of neurons and/or sponge-like change of neuropile in nucleus caudatus of the cerebrum, necrosis and partial disappearance of granular cells and Purkinje's cells, and swelling of Bergmann's cells in the cerebellum. In survived animals, the relative organ weight in the liver increased in males given 300 mg/kg/day or more and females given 1800 mg/kg/day, and histopathological examination revealed slight vacuolization, hypertrophy of centrilobular hepatocytes in males given 1800 mg/kg/day. Furthermore, in some females, similar changes of the cerebrum and the cerebellum, as mentioned above, were slightly observed. In electron microscopic examination, slight proliferation of smooth endoplasmic reticulum in hepatocytic cytoplasm was observed in males given 1800 mg/kg/day. The necrobiotic changes, such as condensation of nuclear chromatin, increased electron density of cytoplasm and nuclei, mitochondrial accumulation and vacuolization, in the cells possibly derived from small granular cells in the cerebellum were observed in females given 1800 mg/kg/day. The mitochondrial swelling, decreased and dilated rough endoplasmic reticulum, and increased electron density of cytoplasm and nuclei with formation of cytoplasmic vacuole and membranous degenerated structure in neurons of cerebral temporal lobe cortex were observed in females given 1800 mg/kg/day. 6. In a recovery study, electron microscopic examination revealed a slight degeneration of myelinated nerve fibers in the cerebellum in males given 1800 mg/kg/day. On the contrary, there were no remarkable changes in general condition, body weight and various clinical parameters. It was noted that these changes induced by IPD-1151T seemed to be reversible changes.(ABSTRACT TRUNCATED AT 400 WORDS)

A thirteen-week oral repeated dose toxicity study of suplatast tosilate (IPD-1151T) in dogs

A 13-week oral repeated dose toxicity study of suplatast tosilate (IPD-1151T), a new anti-allergic agent, as well as a 5-week recovery study were carried out at dose levels of 0 (control), 50, 150, 450 and 1350 mg/kg/day using male and female beagle dogs. The results were as follows: 1. In general conditions, soft feces and diarrhea with specific smell were dose-dependently observed in males and females given 450 mg/kg/day or more. Both sexes given 1350 mg/kg/day, revealed reeling with dropped head, abnormal gait, dysstasia, lying at lateral or prone position, sedation, and tremor, and one male and one female in this group died after showing respiratory depression, collapse and cyanosis. 2. There were no significant or remarkable changes in body weight, food consumption, water consumption, ophthalmology, electrocardiogram, urinalysis, hematology, biochemistry, fecal occult blood test, and absolute and relative organ weights. 3. Pathological examination in dead animals revealed hemorrhagic change in the heart and slight vacuolar changes in hepatocytes. In survived animals, there were no pathological changes attributable to the IPD-1151T. 4. In electron microscopic examination, there were no abnormalities in the liver and kidney attributable to the IPD-1151T. 5. After 5-week recovery period, above-mentioned changes disappeared. 6. From the above results, the non-effective dose level and the toxic dose level were estimated to be 150 mg/kg/day and 1350 mg/kg/day, respectively, and no sex differences were found.

Toxicity, tissue distribution, and excretion of benzyl chloride in the rat.

The tissue distribution and excretion of [14C]benzyl chloride was investigated in adult male and female Fischer 344/N rats after administration of a single oral dose of [14C]benzyl chloride in corn oil at 25 mg/kg, data was correlated with histopathologic and toxicity findings elicited from a 27-37-wk repeated-dose oral toxicity study of benzyl chloride. Radioactivity was detected in all tissues selected for examination. Elimination of the isotope occurred predominantly in the urine. Female rats excreted the isotope at a faster rate than the males and also maintained slightly lower tissue concentrations (with the exception of the blood and kidneys). Isotope recovery was achieved at 90% in the urine and feces of female rats at 24 h, compared with an 80% recovery rate in males. Concentrations of radioactivity were high in the gastrointestinal tract, reflecting the route of administration; however, the squamous stomach and the small intestine consistently retained higher concentrations of isotope than the glandular stomach. Results of acute toxicity and organ histopathology studies in animals dosed with benzyl chloride for 27-37 wk are compatible with the organ distribution and excretion of [14C]benzyl chloride. Histopathologic findings included severe acute and chronic gastritis, hyperkeratosis and hyperplasia of the squamous stomach, and progressive lesions of the heart ranging from proliferation of interstitial cells to acute necrosis of myocardial fibers. Both of these studies suggest that the squamous stomach is a target organ for benzyl chloride or one of its metabolites.