Roles of Na and Cl ions in Basal and Angiotesin II-Stimulated Aldosterone Secretion in Vitro by Bovine Adrenal Glomerulosa Cells

The aim of this study was to observe basal and angiotensin II (All)-stimulated aldosterone secretion in vitro by isolated bovine adrenal glomerulosa cells in the presence of varying concentrations of Na ion, and also to investigate the dependency of aldosterone secretion on extracellular Cl ion. When Na in the incubation medium was replaced iso-osmotically by choline or N-methylglucamine, the absence of Na markedly inhibited basal and All-stimulated aldosterone secretion, and concentrations of Na below 50mM impaired the ability of adrenal glomerulosa cells to respond to All. Basal aldosterone secretion was significantly higher at Na concentrations of 50 and 93mM in the choline substitution experiment, as compared with the normal concentration of Na, and the increment in aldosterone above basal levels by All stimulation reached a maximum at a Na concentration of 93mM. The absence of Cl ion in the incubation medium didn’t alter aldosterone secretion as Cl(−) was replaced totally by [Formula: see text] From these results, we conclude that extracellular Na ion appears to play an important role in the aldosterone secretion by isolated bovine adrenal glomerulosa cells.