The Enrichment of Adenylate Cyclase in the Plasma Membrane and Golgi Subcellular Fractions of Porcine Adenohypophysis

Adenylate cyclase has been found to be associated with par t i cu la te fractions from various m a m m a lian cells and unicellar organisms (for review see reference 16). Mostly, the enzyme has been associated with the plasma membrane , a l though in brain it was conta ined in the synaptic membranes (3), in the rabbi t psoas muscle in the microsomal fraction (15), and in the lymphocyte on the plasma and nuclear membranes (17). Al though hypotha lamic releasing factors seem to st imulate the secretion of certain hormones from adenohypophysis through adenylate cyclase and cyclic A M P (16), the subcellular dis tr ibut ion of the enzyme has not been studied. This prel iminary communica t ion reports the finding of marked enr ichment of adenylate cyclase in the p lasma membrane and Golgi fract ions of porcine adenohypophysis . These subcellular fract ions were each enriched in their respective components but cross-contaminat ion did exist as shown by electron microscope and enzyme marker studies. M A T E R I A L S A N D M E T H O D S