In order to study the effects of female sex hormones and oral contraceptive on hepatic tumorigenesis in rats fed with p-dimethylaminoazobenzene, growing female albino rats, which weigh 70-90gm were fed with 0. 06% p-dimethylaminoazobenzene in basal diet for 4 months, and injected or administered with estrogen, progesterone and oral contraceptive, respectively. As a result of study, I have obtained the following results;
1. The incidence of hepatic nodular hyperplasia, hepatic cell adenomas and hepatocellular carcinomas was highest in the case of estrogen-injected and oral contraceptive administered groups, whereas the incidence of estrogen plus progesterone-injected or progesterone-inje-cted groups were lower than that of the control rats fed with p-dimethylaminoazobenzenene.
2. The incidence of cholangiofibrotic nodules and cholangiocarcinomas was, more or less higher in the case of estrogen-injected and oral contraceptive-administered rats than those of the other groups.
3. Fibrotic changes in the liver were also more extensive in estrogen-injected and oral contraceptive-administered groups than those of the others.
4. The rate of increase in body weight ok experimental rats was lowest in oral contra-ceptive-administered group, and highest in estrogen plus progesterone-injected group.
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