A comparative study of the effects of norepinephrine and vasopressin on Na transport and O2 consumption in frog skin.

Experiments were designed to compare the effects of two hormones-vasopressin and norepinephrine-on the energetics of Na transport in frog skin. Simultaneous measurements of O2 consumption and net Na flux were performed in the same skins by means of O2 cathodes and the short circuit current technique. The results showed that both hormones induced similar increments in Na transport. In contrast, there was a conspicuous difference in O2 consumption values, norepinephrine having a very small stimulatory effect compared to the one induced by vasopressin. Thus, despite the fact that both hormones increase Na permeability of frog skin by similar mechanisms and to a similar extent, they appear to exert very different effects on cell metabolism.