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Biomedical subjects

I S Edelman

Publications and source records attributed to I S Edelman.

At least 109 records · Page 6Linked to original sources
PubMed1975

Autoradiographic localization of corticosterone receptors (type III) to the collecting tubule of the rat kidney.

Recently, a class of receptors exhibiting high affinity for corticosterone was described in rat kidney (Feldman, D. et al., Endocrinology 92: 1429, 1973). These receptor sites exhibited negligible affinity for dexamethasone and aldosterone and were designated Type III to distinguish them from sites having high affinity for aldosterone (Type I), and sites with high affinity for dexamethasone and corticosterone (Type II). To visually localize Type III sites in the kidney and demonstrate whether or not they represent intracellular steroid receptors, we used an autoradiographic procedure for diffusible substances. Male adrenalectomized rats were injected intravenously with the following combination of steroids per 100 g body weight: 4 x 10(-9) mol [3H]corticosterone, 4 x 10(-9) mol unlabeled aldosterone, and 4 x 10(-9) mol unlabeled dexamethasone. To differentiate "nonspecific" binding, each experimental animal was paired with a control animal that received the same steroids plus 250-fold unlabeled corticosterone. At 3 min, 10 min, and 30 min, kidneys were removed, cut into quadrants, and frozen in isopentane cooled by liquid nitrogen. For autoradiography, 4 mum frozen sections were cut, pressed into contact with emulsion precoated slides at -30 C, melted and simultaneously dried under a jet of dry nitrogen gas, and exposed at 4 C for 2 to 6 weeks. At all three time intervals, silver grains representing [3H]corticosterone binding sites, were concentrated over collecting tubules, only in the outer medulla and cortex (those in the inner medulla and papilla were not labeled). In the labeled segments of the nephron, some of the cells showed an apparent high ratio of cytoplasmic to nuclear grains and in others nuclear labeling was more prominent. A small population of cells within labeled collecting tubules (possibly dark cells) were not labeled. Although no function can yet be ascribed to Type III receptors in the kidney, they may represent an important steroid-mediated renal mechanism.

Animals↗
PubMed1974

Renal aldosterone receptors: studies with (3H)aldosterone and the anti-mineralocorticoid (3H)spirolactone (SC-26304).

In vivo, a spirolactone (SC-26304) inhibited the effects of aldosterone on urinary K(+):Na(+) ratios and the binding of [(3)H]aldosterone to renal cytoplasmic and nuclear receptors. Cytoplasmic binding of [(3)H]aldosterone and [(3)H]spirolactone (SC-26304) was similar in magnitude and involved the same set of sites. Under three sets of conditions-(i) in the intact rat, (ii) in kidney slices, and (iii) in reconstitution studies (mixing prelabeled cytoplasm with either purified renal nuclei or chromatin), [(3)H]spirolactone (SC-26304) did not yield specific nuclear complexes in contrast to the reproducible generation of these complexes with [(3)H]aldosterone. In glycerol density gradients, cytoplasmic [(3)H]aldosterone receptor complexes sedimented at 8.5 S and 4 S in low concentrations of salt and at 4.5 S in high concentrations of salt. Cytoplasmic [(3)H]spirolactone (SC-26304) receptor complexes sedimented at 3 S in low concentrations of salt and 4 S in high concentrations of salt. These results are discussed in terms of an allosteric model of the receptor system.

Adrenalectomy↗
PubMed1974

Kinetics of RNA labeling in toad bladder epithelium: effects of aldosterone and related steroids.

Sucrose gradient analysis revealed an aldosterone-dependent increase in the incorporation of [(3)H]uridine into a nonmethylated, rapidly labeled RNA that sedimented at 9-12 S. This effect was antagonized by an anti-mineralocorticoid, spironolactone (SC 9420), and was not elicited either by a glucocorticoid, cortisol, or by the inactive isomer, 17-alpha-isoaldosterone. These findings are in accord with the inference that mRNA is induced by aldosterone during the latent period and that the induced mRNA mediates the action on sodium transport.

Aldosterone↗