PRIMING EFFECT OF LUTEINIZING HORMONE RELEASING FACTOR: IN-VITRO STUDIES WITH RAISED POTASSIUM ION CONCENTRATIONS

Abstract

Department of Human Anatomy, South Parks Road, Oxford, 0X1 3QX (Received 1 January 1976) Under certain conditions, luteinizing hormone releasing factor (LH-RF) exerts a priming effect on pituitary gonadotrophs. Thus, in terms of luteinizing hormone (LH) secretion, the response to the second of two exposures to the factor (in vivo and in vitro) is significantly greater than that to the first (Aiyer, Chiappa & Fink, 1974; Pickering & Fink, 1976), and, if the pituitary is exposed to constant increased levels of LH-RF, the secretion of LH increases exponentially after 45–60 min (Fink, Chiappa & Aiyer, 1976). The full development of the priming effect can be blocked by inhibitors of protein synthesis (Fink & Pickering, 1975; Pickering & Fink, 1976), suggesting that the effect depends upon a newly synthesized protein. This protein may be new LH, or some compound acting on the LH-RF receptor or LH release mechanisms. Samli & Geschwind