Endogenous and exogenous modificators of Na,K-ATPase activity

Preincubation of the rat brain and liver homogenates with acetylcholine (noradrenaline) leads to a decrease (increase) in Na,K-ATPase activity and to a release of dialysate of the low-molecular factor activating (desactivating) Na,K-ATPase of intact microsomes. The acetylcholine (noradrenaline)-induced synthesis of activating (desactivating) factors and inhibition (activation) of Na,K-ATPase synthesis were revealed. A new low-molecular factor activating enzymes was isolated and characterized. Some N-oxides of pyridine and quinoline derivatives in concentrations ranging from 10 -4 to 10 -10 M inhibit Na,K-ATPase activity in cattle brain microsomes. A new Na,K-ATPase activator, 2-(2,4-dimethoxystyryl) quinoline-N-oxide), has been found, which is capable of acting at concentrations within 10 6-10 -9 M. Since these compounds activate enzymes in very low concentrations, they can probably be effective in treatment of some disorders involving violation of the Na,K-ATPase function.