Deciduomal response in androgenized rats: effect of age and steroid replacement therapy

Deciduomal response was studied in female rats androgenized with a single injection of 1 mg of testosterone propionate at 5 days of age. Endometrial scratching in immature rats (33 days) elicited a better response in androgenized rats (AF) than in controls (NF) following induction of ovulation or steroid replacement therapy. In adult females receiving cervical stimulation at estrus or induction of ovulation, strong deciduomal response was obtained in NF rats and no response was observed in AF rats. In ovariectomized (OVX) rats receiving 2 mg of progesterone (P), the response in AF was only 50% that of NF rats. Addition of 0.1 mg of estradiol (E2) enhanced the decidualization in NF rats but completely abolished that of AF rats. Following ovariectomy and a period of 12-15 days without any exogenous hormone, an E2 priming treatment (0.2 or 0.5 micrograms) for 3 days followed by a replacement therapy (2.0 mg P + 0.1 or 0.15 micrograms E2) allowed good response in NF rats. The response was reduced by 30-35% in AF rats receiving 0.1 micrograms of E2 during the replacement therapy and by 66% in AF rats receiving 0.15 micrograms of E2. These results indicate that in AF rats the reduction of the response is age dependent, the uterus is more sensitive to E2 than is the uterus of NF rats and the growth response is always submaximal.