The influence of ovarian hormones on the decidual alkaline phosphatase reaction in adrenalectomized pseudopregnant rats

SUMMARY The influence of oestradiol-17β and/or progesterone on decidual alkaline phosphatase was studied in adrenalectomized (day 1) and ovariectomized (day 1) rats after uterine traumatization on day 4 of pseudopregnancy. Enzyme activity was 10–15 times greater on day 8 of pseudopregnancy in untreated adrenalectomized and intact animals than in non-decidualized uteri. Treatment of ovariectomized and/or adrenalectomized rats with seven daily injections of 5 mg progesterone alone or combined with oestradiol-17β (0·1 μg on days 1–3, and 1·0 μg on days 4–7), did not alter the enzyme reaction. If 1·0 μg of the oestrogen was administered with 5 mg progesterone from days 1–7, no deciduoma response was observed. The results substantiate the hypothesis that progesterone is the only ovarian and adrenal hormone necessary for decidualization of traumatized uteri in pseudopregnant rats.