ROLE OF HUMORAL AGENTS IN VOLUME EXPANDED HYPERTENSION

Increased salt intake or decreased salt excretion [in animals and humans] leads to elevated blood pressure and increased extracellular salt and volume. The blood pressure rises slowly and for this reason and others cannot be explained by the increased salt or volume per se. It appears that pressure rises as a result of some indirect effect of the increased volume. Autoregulation was implicated, but reasons are presented which make this an unlikely possibility. Recent evidence suggests that some humoral agent or agents, operating through the Na+-K+ pump in cardiovascular muscle, participate in the genesis of volume expanded hypertension.