Progesterone and estrogen control of uterine prostaglandin dehydrogenase activity during deciduomal growth

Prostaglandin, dehydrogenase activity was determined in deciduomal and myometrial tissues during growth and regression of the deciduoma during pseudopregnancy. The hormonal control of prostaglandin dehydrogenase activity in these tissues was determined in experiments with ovariectomized pseudopregnant rats. Prostaglandin dehydrogenase activity for both prostaglandin E1 (PGE1) and prostaglandin F2alpha (PGF2alpha) in deciduomal and myometrial tissues increased during the growth of the deciduoma and decreased during the regression phase. No prostaglandin dehydrogenase activity was detected in non-decidualized pseudopregnant rat uteri. In ovarictomized pseudopregnant rats, progesterone and estrogen increased prostaglandin dehydrogenase activity for PGE1 in the deciduoma and myometrium; no synergistic action of the hormones was observed. Progesterone increased prostaglandin dehydrogenase activity for PGF2alpha in the deciduoma, but had no effect in the myometrium. The increases during decidualization in dehydrogenase activity for PGE1 and PGF2alpha, and the enhanced inactivation of these luteolytic substances would provide an explantation for the prolonged pseudopregnancy which results from decidualization of the uterus.