Natriuretic effect of chronically administered alpha-human atrial natriuretic polypeptide in sodium depleted or repleted conscious spontaneously hypertensive rats.

Hypotensive and natriuretic effects of chronically administered alpha-human atrial natriuretic polypeptide (alpha-hANP) were investigated in conscious spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) in both sodium depletion and repletion. Systolic blood pressure was significantly reduced in SHR and WKY in both sodium deplete and replete states. Urinary sodium excretion was significantly increased in SHR and tended to be increased in WKY on sodium repletion, but remained unchanged on sodium depletion. It is suggested that extracellular fluid volume may be an important determinant factor of the natriuretic action of ANP but may not affect the hypotensive effect.