Some feed-back mechanisms by drugs in the interrelationship between the active transport system and adenyl cyclase system localized in the cell membrane

Abstract

The Na +-K +-dependent (transport) ATP-ase was prepared from rat heart and gastric tissues, human gastric mucosa and the effects of adrenaline, atropine, acetylcholine, neostigmine and NaF were tested on it. The experiments presented have shown that adrenaline and atropine in a wide range of concentrations of NaF cause a highly significant inhibition of Na +-K +-dependent ATP-ase from four types of tissues; acetylcholine and neostigmine were without effect. Interrelationships between the active transport ATP-ase system and adenyl cyclase system are discussed. From the effects of drugs on both systems under in vitro conditions it is concluded that (i) the transport ATP-ase system is 100- to 1000-times more sensitive to drugs than the adenyl cyclase system, (ii) the stimulation by drugs of adenyl cyclase is associated with blocking of Na +-K +-dependent ATP-ase activity, (iii) activity of Na +-K +-dependent ATP-ase present in the incubation system causes inhibition of adenyl cyclase activity, (iv) the products of adenyl cyclase activity (cyclic adenosine 3′,5′-monophosphate and adenosine 5′-monophosphate) directly inhibit the Na +-K +-dependent ATP-ase activity, (v) the active transport ATP-ase system and adenyl cyclase system are separate.