Stimulation of adenylate cyclase in isolated rat glomeruli by prostaglandins

Abstract

The effect of prostaglandins and various agents on cyclic adenosine 3',5'-monophosphate generation was studied in isolated rat glomeruli. Specific activity of adenylate cyclase in the glomeruli showed a 12-fold increase over the crude homogenate and a fivefold increase over a tubular preparation. Prostacyclin (PGI2) preferentially stimulated adenylate cyclase of isolated glomeruli at a concentration as low as 10(-9) M. Prostaglandins (PGE1, PGE2, and PGA2) and parathyroid hormone (1–34 synthetic PTH fragment) increased adenylate cyclase in glomeruli with maximal stimulation at 2 X 10(-5) M and 2–4 microgram/ml, respectively. No inhibition of PGE2 on PTH stimulation was observed. Isoproterenol (2 X 10(-4) M) caused a small stimulation, while PGF2alpha, arginine vasopressin, and angiotensin II were ineffective. The presence of guanosine triphosphate in the adenylate cyclase assay enhanced basal and PGE2- and PTH-stimulated activity, but had no effect on NaF stimulation. These findings show an effect of prostaglandins and PTH on the glomerular cAMP system and raise the possibility of a physiological action of these agents on the glomerulus.