STIMULATION OF PROSTAGLANDIN ACCUMULATION IN THE RAT ANTERIOR PITUITARY GLAND BY LUTEINIZING HORMONE RELEASING HORMONE IN VITRO

Abstract

The addition of luteinizing hormone releasing hormone (LH-RH) to cultures of monolayers of rat anterior pituitary cells was shown to increase both the concentrations of prostaglandins E₁ and E₂ (PGE) in the cells and the release of LH over similar ranges of concentrations of LH-RH (10⁻⁶ to 10⁻¹⁰ mol/l). The peak concentration of PGE was observed after 2·5 h. The stimulation of the level of PGE in the cells by LH-RH was completely inhibited by two inhibitors of prostaglandin synthetase, which only partially inhibited the stimulation of LH release. Therefore the increased concentration of PGE was not obligatory for the effect of LH-RH on LH release. It was also shown that monobutyryl cyclic AMP stimulated the intracellular concentration of PGE and it is suggested that the stimulation of PGE levels may be mediated by increased levels of cyclic AMP in the cells after the addition of LH-RH.