INFLUENCE OF THE LIVER ON VASCULAR REACTIVITY

Abstract

The liver participates in the mechanism concerned with the control of the responsiveness of the cardiovascular system to vasoactive substances. Loss of its influence leads to a refractory state, overcome only to a small degree by fresh blood and tetraethylammonium. The nervous system, on the contrary, tends to reduce responsiveness because, when destroyed, pressor-depressor action is greatly augmented. When hepatectomy and spinal cord destruction are combined the net effect despite the different mechanisms concerned seems to be a resultant of the opposing forces. The kidneys also act to reduce responsiveness, for on their removal, it increases. Tachyphylaxis to renin is caused by multiple factors, among them being reduction of renin-substrate, inhibition by the autonomic nervous system, and kidneys. The lack of response after hepatectomy seems chiefly caused by tachyphylaxis, resulting from renin excreted during and after the operation of hepatectomy along with exhaustion of renin-substrate by repeated renin injns.