Chemical and clinical studies of endogenous digitalis-like factor in hypertension

• Published in: Annals of the New York Academy of Sciences 1986-12, Vol.488 (1 Membrane Path), p.217-227
• Main Authors: Cloix, J F, Devynck, M A, Meyer, P
• Format: Article
• Language: English
• Subjects: Adult; Aged; Animals; Cardenolides; Digoxin; Female; Humans; Hypertension - metabolism; Hypertension, Renal - metabolism; Ion Channels - metabolism; Male; Middle Aged; Rats; Rats, Inbred Strains; Saponins; Sodium - administration & dosage; Sodium - metabolism; Sodium-Potassium-Exchanging ATPase - antagonists & inhibitors; Sodium-Potassium-Exchanging ATPase - metabolism
• ISSN: 0077-8923; 1749-6632
• DOI: 10.1111/j.1749-6632.1986.tb46560.x

Endogenous digitalis-like factor (endalin) was investigated by measuring the ability of rat and human plasma and urine to inhibit [3H]ouabain-specific binding, digoxin-antidigoxin antibodies interaction, and renal Na+, K+-ATPase activity. Endalin was detected in plasma (and urine) of one third of 112 patients with sustained and moderate hypertension (Na+ intake = 110 mmol/l). Endalin tended to be increased in the more pronounced hypertensives. No correlation with any other clinical and biological parameter could be detected. An activity to inhibit Na+, K+-ATPase was also detected in the rat after acute and chronic Na+ loading, in reduced renal mass-type hypertension and in SHRs as compared to WKY rats. Comparison of the plasma and urine inhibitory effects in the different tests revealed some chemical heterogeneity. However, a compound possessing the biochemical and pharmacological characteristics of digitaline was extracted from human urine. Chromatographic and spectral analysis of about 1,000 liters revealed a compound with apparent chemical homogeneity, molecular weight around 500, devoid of peptidic bound and of aliphatic structure.