digoxin and Fibrocystic-Breast-Disease

Digoxinlike materials (DLMs) are compounds found in animals that (1) cross-react with digoxin antibodies in specific radioimmunoassay procedures and (2) bind to Na+, K(+)-ATPase and inhibit its activity. DLMs may play a part in the regulation of electrolyte composition. We have determined DLM concentrations in breast cyst fluids and found that these fluids were a rich source of DLMs. Total DLMs were elevated in fluids with type 1 electrolyte composition (high K+ and low Na+ content) when compared to fluids with type 2 composition (low K+ and high Na+ content). Chromatographic studies showed that the basis for the increase was the presence of an additional DLM in the type 1 cyst fluids rather than an increased concentration of the same DLM present in both types of fluids. We propose that this additional DLM may have a role in the accumulation of K+ ions in type 1 fluids. In addition, 7 of 80 cyst fluid samples subjected to high-performance liquid chromatography had a large UV-absorbing peak at 6.4 minutes. Four of these samples were taken from women who later developed breast cancer; information on the subsequent medical history of the other 3 women was unavailable. We suggest that the presence of this material in cyst fluid may be a marker of risk for development of breast cancer.

Topics: Biomarkers, Tumor; Blood Proteins; Cardenolides; Chromatography, High Pressure Liquid; Digoxin; Exudates and Transudates; Female; Fibrocystic Breast Disease; Humans; Potassium; Radioimmunoassay; Saponins; Sodium; Sodium-Potassium-Exchanging ATPase