Partial Purification of a Sodium Pump Inhibitor from Bovine Adenohypophysis. Its Comparison with the Natriuretic Factor Isolated from Hypothalamus

Abstract

Adenohypophysis and hypothalamic bovine tissues were homogenized, lipid extracted, salt removed and loaded onto 2 successive μBondapak HPLC columns, semipreparative and analytic, respectively. In vitro sodium-pump inhibitory activity, recovered from each tissue, showed similar chromatographic patterns, but hypothalamus seems to contain a major hydrophobic material which appears at the end of the run, when acetonitrile gradient raised 40%' approximately. Digitalis-like activity disappears along the purification procedure, and this fact suggests a clear dissociation between (Na/K)ATPase inhibition and digoxin-like activity, measured as crossing with digoxin antibodies.

Key Words:

• Sodium-pump
• adenohypophysis
• hypothalamus
• ouabain binding
• digoxin-like
• natriuretic factor