Some Effects of Energy-Transfer Inhibitors and of Ca++-Free or K+-Enhanced Media on the Release of Luteinizing Hormone (LH) from the Rat Pituitary Glandin Vitro1

Abstract

The hypothalamic extract-stimulated release of luteiniz ing hormone (LH) from the rat pituitary incubated in vitro was found to be dependent upon the presence of Ca++ in the medium. When the K+ concentration of the medium was increased to 59 mM the release of LH was much stimulated as compared to controls in 5.Fm[image] K+. When hypothalamic extract and 59 m[image] K+ were both present the stimulatory effects on LH release were additive. The 59 m[image] K+-stimuIated release of LH was also dependent upon the presence of Ca++. However, absence of Ca++ did not inhibit, nor did excess K+ stimulate, the incorporation of 14C-leucine into LH. At concentrations of dinitrophenol and oligomycin where 75% of the incorporation of 14C-leucine into LH was inhibited the release of LH was not affected. These results indicate that the synthesis and release of LH are separate phenomena.