LaBella F S, Templeton J F
Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
Clin Exp Hypertens. 1998 Jul-Aug;20(5-6):601-9. doi: 10.3109/10641969809053238.
Steroid binding domains of Na,K-ATPase and the nuclear hormone receptors share amino acid sequence homologies. In a ouabain radioligand assay, the potencies of series of planar or bent steroid moieties suggest that the domain in Na,K-ATPase can accommodate compounds with a planar configuration. The A/B -cis, C/D-cis steroid configuration in the cardenolides, in conjunction with appropriate substituents at the 3 and 17 positions, may represent a fortuitous "fit" for the exogenous compounds. It remains to be determined if the putative physiological digitalis-like substance is a member of a hormonal steroid family, an endogenous ouabain-like compound or both.
