Effect of Growth Hormone on Sodium Transport and Osmotic Water Flow Across Toad Skin

Abstract

In order to determine the mode by which growth hormone causes sodium and water retention in animals, its action was studied using isolated toad skin. Within minutes, after adding ovine or bovine growth hormone to the medium bathing the inside of the isolated skin, there was an increase in sodium transport and osmotic water movement across the skin. Pretreatment of skins with growth hormone or antidiuretic hormone abolished or reduced stimulation of sodium transport by the other hormone. Similarities between the actions of these two hormones suggested a common mode of action. Demonstration of significant pressor activity in the ovine and bovine growth hormone preparations and lack of stimulation of sodium transport or osmotic water flow across isolated toad skin by highly purified growth hormone lead us to conclude that the sodium and water retaining actions of ovine and bovine growth hormone may be due to contamination with neurohypophysial hormones.

Key words

Growth Hormone - Sodium Transport - Osmotic Water Flow - Toad Skin