Bibliographic Citation
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Title | Mineralocorticoid receptors along the nephron: (/sup 3/H)aldosterone binding in rabbit tubules |
Creator/Author | Doucet, A. ; Katz, A.I. |
Publication Date | 1981 Dec 01 |
OSTI Identifier | OSTI ID: 5655901 |
Other Number(s) | CODEN: AJPHA |
Resource Type | Journal Article |
Resource Relation | Am. J. Physiol. ; Vol/Issue: 241:6 |
Research Org | Univ. of Chicago, IL |
Subject | 550201 -- Biochemistry-- Tracer Techniques; ;MINERALOCORTICOIDS-- BIOCHEMISTRY;TUBULES-- RECEPTORS; ALDOSTERONE;KIDNEYS;RABBITS;TRITIUM COMPOUNDS |
Related Subject | ADRENAL HORMONES;ALDEHYDES;ANIMALS;BODY;CHEMISTRY;CORTICOSTEROIDS;HORMONES;HYDROXY COMPOUNDS;KETONES;KIDNEYS;LABELLED COMPOUNDS;MAMMALS;MINERALOCORTICOIDS;ORGANIC COMPOUNDS;ORGANS;PREGNANES;STEROID HORMONES;STEROIDS;VERTEBRATES |
Description/Abstract | To identify the site of mineralocorticoid action along the nephron, we measured the specific binding of (/sup 3/H)aldosterone to nephron segments microdissected from aldosterone-deficient rabbits.^Specific binding was defined as the difference between binding measured in the absence or in the presence of 2,000-fold excess of unlabeled hormone (in 10/sup -18/ mol.cm tubule length/sup -1/ +/- SE).^High specific binding capacity was found in the branched collecting tubule (108 +/- 4), the cortical collecting tubule (119 +/- 9), and the outer medullary collecting tubule (115 +/- 16), whereas specific binding was negligible in the proximal convoluted tubule (8 +/- 9), pars recta (2 +/- 6), medullary thick ascending limb (4 +/- 6), cortical thick ascending limb (6 +/- 2), and distal convoluted tubule (6 +/- 6).^In cortical collecting tubules, Scatchard analysis of the specific (/sup 3/H)aldosterone binding indicated a dissociation constant (K/sub D/) of 2.2 X 10/sup -9/ and a maximum number of binding sites of 157 X 10/sup -18/ mol.cm tubule length/sup -1/.^The steroid specificity was assessed from the competition of various steroids for (/sup 3/H)aldosterone binding sites.^Receptors from the cortical collecting tubule revealed the following sequence of affinities: aldosterone > DOCA > spironolactone > dexamethasone > 5..cap alpha..-dihydrotestosterone = progesterone = 17..beta..-estradiol, indicating that the binding sites in the collecting tubule are mineralocorticoid receptors.^ These results demonstrate significant (/sup 3/H)aldosterone binding to receptors of high affinity and mineralocorticoid specificity only in the collecting tubule and suggest that this nephron segment is the target site of mineralocorticoid action in the rabbit kidney. |
Country of Publication | United States |
Language | English |
Format | Pages: F605-F611 |
System Entry Date | 2001 May 13 |
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