A Role for the Adrenal Renin-Angiotensin System in the Regulation of Potassium-Stimulated Aldosterone Production*

Abstract

Potassium is a major regulator of aldosterone production. It also increases adrenal renin. The causal relationship between potassium and adrenal renin is not known. To evaluate the role of the intraadrenal renin-angiotensin (ANG) system in potassium-stimulated aldosterone synthesis and release, specific adrenal renin activity, PRA, and plasma aldosterone were measured during potassium loading or captopril treatment in the rat. Adrenal ANGs were determined using a HPLC system combined with RIA to obtain quantitative information on the components of the adrenal renin-ANG system. In addition, the effect of pretreatment with captopril on aldosterone production by isolated adrenal glomerulosa cells was examined. In intact animals potassium loading markedly increased adrenal renin and plasma aldosterone, whereas PRA was suppressed. The administration of captopril to rats in normal potassium balance did not suppress plasma aldosterone. Captopril treatment during potassium loading inhibited the potassium-induced increase in aldosterone. Furthermore, pretreatment with captopril suppressed adrenal ANG II and reduced the response of aldosterone production to extracellular potassium concentration by isolated adrenal glomerulosa cells in vitro. These results suggest that the adrenal renin-ANG system plays a significant role in the control of aldosterone production under potassium stimulation.

Effect of Atrial Natriuretic Peptide on Adrenal Renin and Aldosterone.

“…Studies on the interaction of adrenal renin and aldosterone have demonstrated the presence of adrenal tissue angiotensin I, II, III and angiotensinogen (Nakamura et al, 1985, Ganten et al, 1976, Mendelsohn 1984. The findings obtained support the concept of a local system for the renin-angiotensinaldosterone axis.…”

“…Accumulated results of studies on adrenal renin have suggested that this enzyme is closely related to aldosterone release (Doi et al, 1984, Nakamura et al, 1985. However, the mechanism by which adrenal renin controls aldosterone release is unclear.…”

“…It is generally accepted that renin-like enzyme in the adrenal gland participates in the regulation of aldosterone production (Doi et al, 1984, Nakamura et al, 1985. Recently, the existence of intrinsic renin, angiotensin I, II and III was demonstrated in the adrenal gland (Nakamura et al, 1985) and the concept of this acting as a local modulating system for aldosterone production was emphasized.…”

“…Recently, the existence of intrinsic renin, angiotensin I, II and III was demonstrated in the adrenal gland (Nakamura et al, 1985) and the concept of this acting as a local modulating system for aldosterone production was emphasized. On the other hand, after the existence of an inhibitor of aldosterone release was suggested in the dog atrium (Anderson et al, 1959), mammalian artrial granule peptide was detected (Currie et al, 1984) and studies on the inhibition of aldosterone production by this peptide were undertaken , Goodfriend et al, 1984.…”

Angiotensin II Generation in Mesenteric Arteries in Rats: Effects of Nephrectomy, Deoxycorticosterone and Dexamethasone.

“…Secondly, the potassium ions accumulated following nephrectomy may stimulate vascular renin production as demonstrated in adrenal renin which is increased after potassium loading in the presence of a suppressed plasma renin level (Nakamaru et al, 1985). Thirdly, a role of the sympathetic nerve activation in the stimulation of vascular ANG II generation (Nakamura et al, 1986) following nephrectomy has yet to be proven.…”