Absence of renal action of pure intermediate lobe hormone.

The action of melanophore expanding hormone of the intermediate lobe of the pituitary (MSH) on the urinary excretion of water, Na, K and Cl was studied in the conscious dog both during water diuresis and in the non-diuretic state. Doses of up to 2.3 IU MSH did not influence renal function. MSH did not modify the renal actions of vasopressin or oxytocin. The antidiuretic action of a massive dose of MSH was attributed to contamination by vasopressin.