Oabain-Like Compound Changes Rapidly on Physical Exercise in Humans and Dogs

Abstract

To the Editor: The article by Bauer et al1 attempts to add further credence to the suggestion that ouabain or a ouabain-like compound is secreted in mammals. The results indicate that under conditions of stress, in this case exercise, there is a dramatic increase in the production of immunologically assayed ouabain. In the studied athletes, this increase was up to 36-fold when expressed as endogenous ouabain immunoreactivity and an 18-fold increase when assayed by inhibition of the sodium pump. Cessation of exercise resulted in a fall in the concentration of ouabain-like compounds with a half-life of ≈3 to 5 minutes, and it …