Sodium and Water Transport across Isolated Intestine of a Marine Teleost

Abstract

THE special osmo-regulatory mechanisms of the marine teleosts were originally outlined by Homer Smith¹; he postulated that these animals maintain a constant blood concentration lower than that of the external sea-water by continual drinking of sea-water and simultaneous excretion of ions mainly through the gills. In addition to this and the work of Keys² on the common eel, several workers, Mullins³ and House⁴, have recently confirmed this theory of osmotic regulation by ion transport experiments in vivo. However, there have been no reported in vitro transport studies of the epithelial membranes involved in the regulation processes. The purpose of the investigation reported here was to determine the magnitude and direction of net transport of sodium and water, if any, across the small intestine of the marine teleost, Cottus scorpius.