Roles of cyclic AMP and inositol phosphates in the luteolytic action of cloprostenol, a prostaglandin F2α analogue, in marmoset monkeys (Callithrix jacchus)

The luteolytic response to a prostaglandin F 2α analogue, cloprostenol, was investigated in vivo and in vitro at defined stages of the luteal phase. In vivo administration of cloprostenol to female marmoset monkeys on day 3 after ovulation had no effect on plasma progesterone concentrations, whereas administration on day 14 after ovulation reduced plasma progesterone to preovulatory concentrations within 4 h. To identify the cellular basis for this luteolytic action, marmoset luteal tissue obtained on days 3, 6 and 14 after ovulation was incubated in vitro and progesterone production, cAMP accumulation and phosphoinositide (PI) turnover measured in response to cloprostenol, human chorionic gonadotrophin (hCG) with or without cloprostenol, or dibutyryl-cAMP with or without cloprostenol