PROSTAGLANDINS HAVE NO EFFECT ON SPONTANEOUS AND GONADOTROPIN-RELEASING HORMONE STIMULATED LUTEINIZING-HORMONE RELEASE IN CULTURED RAT PITUITARY-CELLS

Primary cultures of pituitary cells from adult female rats were exposed to increasing concentrations (10-13-10-6 M) of selected prostaglandins (PGE2, PGF2.alpha., PGI2, 6-keto-PGF1.alpha. and sulproston). The release of luteinizing (LH) by the pituicytes was monitored. In a 2nd series of experiments, pituitary cells were treated with PG as described above and additionally challenged with a submaximal stimulus of gonadotropin-releasing hormone (GnRH; 10-9 M). The spontaneous LH-release in all PG-treated cultures did not differ from the controls. When stimulated with 10-9 M GnRH, the LH-release increased .apprx. 6-fold in all cultures, with no difference between PG-treated cells and the respective controls. The PG tested, at least at concentrations .ltoreq. 10-6 M, have neither a direct positive or negative effect on pituitary LH-release, nor do they enhance or decrease the LH-releasing effect of GnRH. These PG are probably not involved in the cellular regulation of LH-release by the pituicyte. [Implications for the reproductive system, i.e., involvement of PG in mediation of estrogen effects, are considered.].