A ROLE FOR PROSTAGLANDINS IN DECIDUALIZATION OF THE RAT UTERUS

Abstract

The deciduogenic action of various kinds of prostaglandin (PG), i.e. PGE1, PGE2, PGF2α and PGI2, methylated prostaglandins (15-met-PGE1, 15-met-PGE2 and 15-met-PGF2α), PGF2α-13-dehydro analogues (13-DH-PGF2α, ent-15-epi-13-DH-PGF2α), endoperoxide analogues (15S)-hydroxy-9α,11α-(epoxymethano)-prosta-5Z,13E-dienoic acid (U 44069) and (15S)-hydroxy-11α,9α-(epoxymethano)-prosta-5Z,13E-dienoic acid (U 46619), and of the prostaglandin precursor, arachidonic acid, has been demonstrated after intraluminal instillation of these compounds into the uterus of immature rats sensitized with progesterone alone. Under this minimal hormonal stimulation, in which a trauma (a scratch) of the endometrium is required to induce the decidual response, all these compounds elicited the formation of deciduomata, substantiating the suggestion that the scratch-induced decidual reaction is mediated through release of prostaglandin. Confirmation was obtained through the effect of indomethacin and cortisol, both of which decreased the decidual response brought on by a scratch or by arachidonic acid, whereas the effect of PGF2α was decreased by indomethacin but not by cortisol. Histamine, thromboxane B2, and oleic, palmitic and homo-γ-linolenic acids were not deciduogenic. A dose-dependent inhibitory effect of indomethacin on deciduoma formation by instillation of oil into animals sensitized by progesterone plus oestradiol was also observed. The results support the proposal that the decidual reaction involves prostaglandins and we suggest that the deciduoma is a valuable model for studying the action of prostaglandin-related compounds.