Inhibitory effect of somatostatin on the aldosterone response to angiotensin II: in vitro studies
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It has been demonstrated that somatostatin (SRIF) can suppress hypophyseal and extrahypophyseal hormones; moreover, many studies have shown that SRIF inhibits frusemide-induced hyperreninemia in normal man, and renin and aldosterone in renovascular hypertension, possibly through a beta-adrenergic block. To further investigate the possible aldosterone-inhibiting effect of somatostatin, we have carried out in vitro studies using isolated perfused rat zona glomerulosa cells suspended in Biogel. Paired columns were set up and the cells stimulated using either angiotensin II, ACTH, serotonin or potassium. One column was perfused with somatostatin (3–4 ng/ml) and the other was used as a control. Aldosterone was measured by highly specific direct radioimmunoassay. Somatostatin significantly blocked the aldosterone response to angiotensin II but not to ACTH, serotonin or potassium. The inhibitory effect of somatostatin persisted as long as it was added to the medium; the aldosterone response to angiotensin II was progressively restored after discontinuation of the SRIF infusion. From these data it might be suggested that the inhibitory effect of somatostatin on aldosterone production is not cAMP-dependent, since ACTH maintains its stimulatory capacity. The recent demonstration of the presence of specific somatostatin receptors on the rat adrenal cells suggests that its inhibitory effect could be mediated by the second messenger system rather than the interaction with angiotensin II receptors.
Key-wordsSomatostatin angiotensin II ACTH serotonin potassium aldosterone secretion
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- 4.Rosenthal J., Raptis S., Escobar-Jimenez F., Pfeiffer E.F. Inhibition of frusemide-induced hyperreninemia by growth-hormone release inhibiting hormone in man. Lancet 1:772, 1978.Google Scholar
- 5.Arlart I., Rosenthal J., Pal S., Raptis S. Einfluss von somatostatin auf renin, aldosteron und blutdruck bei unilateral renovaskulärer hypertonic Verh. Dtsch. Ges. Inn. Med. 84:824, 1978.Google Scholar
- 8.Aguilera G., Harwood J., Catt K. Somatostatin modulates the effects of angiotensin II (All) in the adrenal glomerulosa zone. Clin. Res. 29:564A, 1981.Google Scholar
- 11.Fujita K., Aguilera G., Catt K.J. The role of cyclic AMP in aldosterone production by isolated zona glomerulosa cells. J. Biol. Chem. 254:8567, 1976.Google Scholar
- 14.Douglas W.W., Kanno T., Sampson S.R. Effects of acetylcholine and other medullary secreta-gogues and antagonists on the membrane potencial of adrenal chromaffin cells: an analysis, employing techniques of tissue culture. J. Phisiol. (Lond.) 188:107, 1967.Google Scholar
- 15.Douglas W.W. Involvement of calcium in exocytosis and the exocytosis-vesciculation sequence. Biochem. Soc. Symp. 39:I, 1974.Google Scholar
- 18.McKenna T.J., Island D.P., Nicholson W.E., Liddle G.W. Stimulation of aldosterone production by catecholamines in vitro. “Sixth International Congress of Endocrinology” Melbourne 1980. Abstracts 395, 1980, p. 407.Google Scholar
- 20.Boscaro M., Al-Dujaili E.A.S., Edwards C.R.W. In vitro studies on the mechanism of inhibition by bromocriptine, lisuride and metergoline of angiotensin II induced aldosterone release. “XII Acta Endocrinologica Congress” (Kbh.) Munich 1979. Abstracts 342, 1979, p. 342. Suppl. 225.Google Scholar