Endogenous digitalis-like natriuretic factors.

There is increasing evidence for endogenous, circulating compounds that interact with the digitalis receptor of [Na,K]ATPase and with antidigoxin antisera. Circulating levels of these digitalis-like compounds increase in response to fluid or salt loading and appear to play a role in diseases characterized by fluid and salt retention, e.g. renal failure, liver disease, acromegaly, experimental and human hypertension, and preeclampsia. Because of assay nonspecificity, many diverse substances are being measured. Of the few compounds currently identified as having "digitalis-like" activity, none appears to be the natural ligand of the digitalis receptor and none appears linked with hypertension. Nevertheless, research still suggests that digitalis-like factors may have a central role in essential hypertension and related disorders.