| Abstract: | Luteal and interstial cell RNA contents and circulating progesterone (P) and 20α-hydroxypregn-4-ene-3-one (20α-OH P) levels were measured during pseudopregnancy in order to characterize relationships between ovarian 20α-OH P secretion and luteal regression. Functional luteolysis, as manifested in depressed P levels, was not associated with concurrent elevations in 20α-OH P. Rather, augmented 20α-OH P levels were evidenced in periovulatory periods at the onset and termination of pseudopregnancy, subsequent to RNA accumulation in both luteal and interstitial compartments. It is postulated that 20α-OH P, the putative inactive metabolite of P, is produced by both ovarian compartments in a cyclic manner and in response to gonadotrophin released in the preovulatory period. |
