Possible Interaction of Anti-diuretic and Sodium-retaining Hormones in the Kidney

Abstract

WHILE investigating the renal excretion of water and sodium by rats in response to intravenous infusion of isotonic saline^1,2, it became desirable to consider some aspects of the renal tubular re-absorption of these substances³. We have attempted to do this by considering a model of the tubules based upon properties of a membrane the characteristics of which have already been studied. Some properties of frog skin have been described by Using and Zerahn⁴, and it seems that this membrane can act as a ‘sodium pump’, actively transferring sodium ions; the activity of the ‘sodium pump’ appearing as an e.m.f. of about 100 mV. across the membrane. The rate of water transfer may be regarded as dependent upon hydrostatic and osmotic pressure differences across the membrane and upon its permeability towater.