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HIGH‐AFFINITY ALDOSTERONE BINDING IN RAT LIVER—A RE‐EVALUATION
Author(s) -
Zaini Anuar,
Pearce Paul,
Funder John W.
Publication year - 1987
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1987.tb00955.x
Subject(s) - aldosterone , endocrinology , medicine , mineralocorticoid receptor , mineralocorticoid , receptor , corticosterone , glucocorticoid receptor , in vivo , binding site , cytosol , chemistry , biology , hormone , biochemistry , enzyme , microbiology and biotechnology
SUMMARY 1. The use of sodium molybdate as a stabilizing agent, and a RU26988 to exclude [ 3 H]aldosterone from Type II glucocorticoid receptors, has enabled us to characterize high affinity Type I aldosterone binding sites in rat liver cytosol. 2. In liver cytosols from male rats aldosterone bound with an affinity (K d ‐22°C) of 0.6 nmol/l (range 0.3–0.8 nmol/l), and N max 1.7 fm/mg protein (s.e.m. = 0.4); specificity of binding was similar to that for Type I sites in classical aldosterone target tissues (aldosterone ≥ corticosterone > dexamethasone). 3. Hepatic Type I receptor levels were relatively constant in both male and female rats aged 30–120 days, with levels significantly higher in females. 4. Parallel studies on hepatoma H4 cells showed levels of Type I sites similar to those in normal liver, suggesting a general distribution of such sites throughout liver parenchyma, rather than a concentration in a specific cell type. 5. The function of such Type I sites, and whether or not they are aldosterone‐selective in vivo and can thus act as mineralocorticoid receptors, remains to be determined.