Sexual Development in Female Rats Treated with Cortisone.

Summary and Conclusions 1. Immature female rats were treated with 1.0 mg of cortisone acetate daily for 2 or 4 weeks starting at 23 days of age and were maintained on pair or ad libido feeding regimes. 2. Body weight, adrenal and thymus weights were reduced compared to control animals. These differences were less marked when animals were autopsied 3 weeks after cessation of treatment. 3. The weights of ovary and uterus were generally greater in the treated animals. The increased weight of the ovaries was due to a greater number of follicles and to an increased size of the antra. 4. Pituitary glands removed from animals treated with cortisone appeared to have a greater gonadotrophic potency than normal as indicated by the growth of the ovaries in immature rats injected with these glands. 5. Possible explanations for these changes are discussed.