A possible non transcriptional effect of progesterone

Abstract

Continuous administration of progesterone and/or estradiol to prepuberal rabbits over a period of 6 days gave dissociated effects on the concentrations in the endometrium of uteroglobin and its messenger RNA. Progesterone increased the messenger content but the uteroglobin concentration rose 3-fold more than could be accounted for by messenger levels. Thus progesterone appeared to have a dual effect: inducing uteroglobin messenger RNA and also exerting a non identified post transcriptional regulation. Time course studies also showed that the effect of progesterone on messenger concentration was very rapid whereas the non-transcriptional regulation was a late hormonal effect. Low and high doses of estrogen associated with progesterone similarly enhanced the induction of uteroglobin mRNA. On the contrary high doses, but not low doses, of estradiol inhibited the hypothetical non-transcriptional effect of progesterone. Estradiol administered alone gave rise to an increase of uteroglobin mRNA but this was accompanied by only a small change in uteroglobin concentration, apparently due to the absence of the non-transcriptional amplification step.