Binding of a Novel Prostaglandin F _2α-derivative (Zk 71 677) To Pseudopregnant Rat Ovaries

Abstract

Prostaglandin (PG)F_2α is believed to regulate the life span of the corpus luteum and this physiologically induced change could be related to the binding properties of PGF_2α in the corpus luteum. Corpora lutea formation was therefore stimulated in juvenile rats with PMSG and HCG. In membrane particles obtained after differential centrifugation, radioligand binding studies were performed with PGF_2α and a novel PGF _2α-derivative (ZK 71 677) on day 7 after HCG admini-stration. Evaluation of the binding parameters revealed a competitive interaction between PGF_2α and ZK 71 677 for the PGF_2α-receptor molecule. When other prostaglandin analogues were used to establish biological potency, the data obtained from receptor binding analysis compared well with the abortifacient potency of these compounds in pregnant rats. The results provide further evidence for the nature and specificity of the PGF_2α-receptor molecule.