Endocrinology, Vol 118, 628-631, Copyright © 1986 by Endocrine Society

ARTICLES

Demonstration of specific high affinity receptors for aldosterone in cytosol of rat colon

HJ Binder, A White, D Whiting and J Hayslett

Since both aldosterone and glucocorticoids increase cation transport in rat distal colon, and a specific glucocorticoid high affinity cytosolic receptor has been identified in this tissue, it was possible that the action of aldosterone was dependent on interaction with the glucocorticoid receptor. Studies were, therefore, performed to determine whether a specific high affinity receptor for aldosterone was present in rat distal colon. At 4 C, aldosterone binding was saturable and exhibited a high affinity site with an apparent Kd of 6.2 +/- 0.9 X 10(-10) M and a calculated number of binding sites of 57.2 +/- 10.8 fmol/mg cytosol protein. Scatchard plot analysis also revealed a low affinity site with a Kd of 5.9 +/- 1.1 X 10(-8) M and 961 +/- 191 fmol/mg cytosol protein-binding sites. Competitive binding studies demonstrated that the high affinity binding protein was specific for aldosterone, compared to either dexamethasone or RU-28362. Since a specific high affinity receptor protein for aldosterone is present in rat distal colon, these data are consistent with a direct action of aldosterone that is independent of the glucocorticoid receptor system.

This article has been cited by other articles:

				K. Kato, H. Sasano, S. Ohara, H. Sekine, S. Mochizuki, T. Mune, K. Yasuda, H. Nagura, T. Shimosegawa, T. Toyota, et al. Coexpression of Mineralocorticoid Receptors and 11{beta}-Hydroxysteroid Dehydrogenase 2 in Human Gastric Mucosa J. Clin. Endocrinol. Metab., July 1, 1999; 84(7): 2568 - 2573. [Abstract] [Full Text]