Active transport of Rb+ across skin of the teleost Gillichthys mirabilis

Abstract

The fluxes of 86Rb were measured across the isolated skin of the marine teleost Gillichthys. The efflux of 86Rb in Cl Ringer with 1.0 mM RbCl exceeded the influx by 8.0 +/- 1.2 neq . cm-2 . h-1 at closed circuit, indicating active transport of Rb+ in the secretory direction. However, the net Rb+ flux was not significantly different from zero in (Cl-free) gluconate Ringer, indicating that the active Rb+ transport was Cl dependent. The epithelium behaved as a single passive resistor to Rb+ in the absence of Cl-, and Rb+ movement under these conditions appeared to be by Fickean diffusion. Epinephrine (10(-5) M) inhibited partially the active Rb+ transport in Cl Ringer. These results suggest that there is active K+ transport across Gillichthys skin.