DIFFERENTIAL RELEASE OF INDIVIDUAL GONADOTROPHINS BY THE HUMAN FOETAL PITUITARY GLAND AFTER STIMULATION BY CYCLIC AMP AND SODIUM FLUORIDE

Work in this laboratory has demonstrated the ability of theophylline to stimulate the release of immunoreactive luteinizing hormone (IRLH) and follicle-stimulating hormone (IRFSH) in organ cultures of human foetal pituitary glands (Groom, Groom, Cooke & Boyns, 1971). Cyclic adenosine 3′,5′-monophosphate (cAMP), while enhancing IRFSH release, had only a minimal effect on the levels of IRLH secreted. The present study extends this work utilizing the organ culture technique and radioimmunoassay methods described previously (Groom et al. 1971). Theophylline, a phosphodiesterase inhibitor (Robison, Butcher & Sutherland, 1968), at a concentration of 10−2 mol/l caused equal stimulation of release of both IRLH and IRFSH from the pituitaries (Table 1). In contrast, 10−2m-cAMP, while stimulating the secretion of both IRLH and IRFSH, had a significantly greater effect on the latter (Table 1). The N6-2′-0-dibutyryl analogue of cAMP (dbcAMP) is more potent both in vivo and in vitro, probably