Effect of ADH on rubidium transport in isolated perfused rat cortical collecting tubules

ADH on rubidium transport in isolated perfused rat cortical collecting tubules. Am. J. Physiol. 250 (Renal Fluid Electrolyte Physiol. 19): F1063-F1072, 1986.-Unidirectional fluxes of =Rb+ were measured as an indicator of potassium transport in isolated rat cortical collecting tubules perfused and bathed at 38°C with isotonic solutions in which Rb ’ replaced K+. Under control conditions the lumen-to-bath flux (&,b) was signifi-cantly less than the bath-to-lumen flux (&.+~), indicating net Rb ’ secretion. Net secretion increased-180 % after addition of 100 pU/ml of arginine vasopressin (ADH) to the bathing solu-tion, due to a rapid and reversible increase in &+I from 4.6 t 0.8 to 9.0 k 1.9 pmol l min-l *mm-l with no significant change in &,. The ADH effect was completely inhibited by 2 mM luminal Ba*‘. The average transepithelial voltage ( Ve) was not significantly different from zero in the control period bu