Chloride-transport stimulatory factor in urine of chronically sodium-chloride loaded man

Urinary extracts (in methylene dichloride) of subjects on high sodium-chloride (NaCl) intake produce net Cl- efflux (active transport) in isolated short-circuited frog skin. Activity is not found in the urine of NaCl-deprived normal subjects or NaCl-loaded subjects with adrenal insufficiency. These findings suggest that presence of an adrenocortical steriod which participates in adaptation to high salt intake. We describe here a lipid-soluble factor extracted from urine of chronically salt-loaded subjects which stimulates active Cl- transport in isolated frog skin. Our findings indicate that the factor is of adrenal origin and that it induces active ion transport in the direction opposite to that stimulated by the adrenal hormone, aldosterone. Aldosterone produces NaCl conservation in states of salt deprivation. We expect this new factor to produce NaCl excretion in states of excess salt ingestion.