EFFECT OF PROSTAGLANDINS ON ADENYLATE-CYCLASE ACTIVITIES IN MEMBRANES FROM LIVER AND TRANSPLANTABLE HEPATOMAS

Abstract

The effects of prostaglandins [PG] on adenylate cyclase activity were examined in membranes purified from normal rat liver and Morris hepatomas. PGE1 gave the greatest stimulation (up to 2-fold) in all membranes. PGA1, PGA2 and PGF2.alpha., although stimulatory in liver and 4 tumor membranes, were inhibitory of adenylate cyclase activity in membranes from 2 of the fast growing tumors. Arrhenius plots yielded broken line curves (at 20.degree. C) for the basal activity of all enzymes. Addition of various PG caused shifts in the broken line curves and/or produced nonbroken (straight) line curves for the liver and many of the hepatoma adenylate cyclases.