Silastic (dimethylpolysiloxane) capsules containing megestrol acetate (6- methyl-17-∝-acetoxypregna-4, 6- diene-3, 20-dione) were implanted subcutaneously in mature female rats. The effects of megestrol on the ovary, on fertility, on body weight, on adrenal weight, and on physical activity were observed. Megestrol acetate did not inhibit ovulation or fertility, and did not reduce ovarian weight; thus it did not have an anti-gonadotrophic effect at the dosages used. It affected vaginal cytology in a typical progestational fashion producing a constant diestrus or mixed cell smear. Body weight increased during treatment and remained fairly constant after treatment stopped. Adrenal weight decreased during treatment and returned to normal after treatment stopped. These two effects may contribute to a decreased physical activity observed in some rats. Continuing obesity after treatment stopped may account for the failure of some rats to regain normal activity. Obesity may also be a factor in the inhibition of mating behavior observed in some of the animals.
Proceedings of the Iowa Academy of Science
©1968 Iowa Academy of Science, Inc.
"Effects of Megestrol Acetate, a Progestin, on Female Rats,"
Proceedings of the Iowa Academy of Science, 75(1), 296-300.
Available at: https://scholarworks.uni.edu/pias/vol75/iss1/40