Production and action of a natriuretic hormone in isolated rat kidneys: necessity of prostaglandins for its release.

A natriuretic factor prepared from plasma of salt loaded rats is active on a totally isolated cell free perfused rat kidney. The progressive increase in fractional sodium excretion with the amounts of injected factor shows a dose-response curve. The inhibition of prostaglandin synthesis does not modify the kidney response to the natriuretic factor. The isolated kidney is able to produce this factor but the inhibition of prostaglandins suppresses its production. Therefore, we conclude that the presence of prostaglandins is a prerequisite for the production but not for the action of the natriuretic hormone.