A rapid and potent natriuretic response to intravenous injection of atrialmyocardial extract in rats (Reprinted from Life Sci, vol 28, pg 89-94, 1981)

Supernatants of atrial or ventricular myocardial homogenates were injected intravenously into anesthetized non-diuretic rats. Extract derived from atr ial muscle caused a rapid, more than 30-fold increase of sodium and chlorid e excretions, while urine volume rose 10-fold, and potassium excretion doub led. No such changes were observed after injection of ventricular tissue ex tract obtained from the same rat hearts, or after injection of the homogeni zation medium. There was no significant difference in glomerular filtration rates between the two groups. We conclude that the atrial extract containe d an extremely powerful inhibitor of renal tubular NaCl reabsorption.