CHARACTERISTICS OF THE CYCLIC 3′, 5′-AMP FORMATION IN ISOLATED OVARIAN FOLLICLES FROM PMSG-TREATED IMMATURE RATS AFTER STIMULATION IN VITRO WITH GONADOTROPHINS AND PROSTAGLANDINS

Abstract

ABSTRACT Isolated pre-ovulatory follicles from PMSG-injected immature rats, described in a previous publication, have been used for the investigation of the pattern of cyclic 3′,5′-AMP synthesis after in vitro addition of gonadotrophins and prostaglandins. The follicles were incubated in a modified Krebs bicarbonate buffer for periods up to 4 h and the cyclic 3′,5′-AMP content in tissue and medium was analyzed with the protein binding assay of Gilman (1970). Addition of LH, FSH or prostaglandin E 2 (PGE 2 ) increased the cyclic 3′,5′-AMP level in follicular tissue dramatically. HCG and TSH, but not STH or prolactin, also induced a similar increase. The effect of FSH was blocked by a highly specific antiserum to LH. The effect of LH had a maximum after approximately 1 h of incubation, whereas the maximal effect of PGE 2 was seen between 5 and 15 min of incubation. When LH was present in the incubation medium a significant release of cyclic 3′,5′-AMP into the medium occurred. Theophylline potentiated the effects of LH and PGE 2 . The different time-courses of the effects of LH and PGE 2 on the cyclic 3′,5′-AMP production by follicular tissue are discussed in relation to the hypothesis of prostaglandins as obligatory mediators of all LH effects on the ovary ( Kuehl et al. 1970).