Physico-chemical characterization of cytosol and nuclear mineralocorticoid receptors in rat kidney

The introduction of a double bond at carbons 6 and 7 (6-dehydro-derivatives) of deoxycorticosterone acetate (DOCA), cortisol-21-acetate, 9 alpha-fluorocortisol-21-acetate (9 alpha-F-C-ac) and aldosterone-21-acetate substantially reduces affinity for Type II receptors but not for Type I receptors. Such a modification changes the effect of these steroids on urinary excretion of Na+ and K+. 6-Dehydro-derivatives will thus bind preferentially to receptor Type I inducing the retention of sodium and compete with mineralocorticoids for such receptors. The increase in both natriuresis and kaliuresis when corticosteroids and their 6-dehydro-derivatives are administered together may be interpreted as evidence for a Type II receptor mediation of those ion fluxes. The ionic changes are not mediated by the (Na+ + K+)-ATPase system. The fluoration at 9 and the dehydrogenation at C9C11 of DOCA result in a strong increase of binding to Type I receptor and of sodium retention.

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“…Incubation was followed by charcoal separation previously described (PALEM-VLIERS et al, 1982). Values reported in Table I …”

Section: Binding Studiesmentioning

confidence: 99%

Effect of various 6-dehydro-corticosteroids, 9,11 -dehydro-DOCA and 9α-fluoro-DOCA on the fluxes of sodium and potassium

Genard¹,

Palem-Vliers²,

Christiaens³

et al. 1989

Archives Internationales de Physiologie et de Biochimie

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“…Recently we have studied and characterized the unactivated and activated forms by sucrose gradient centrifugation and gel electrophoresis (PALEM- VLIERS et al, 1982). Moreover these forms were separated on hydroxyapatite column (unpublished results).…”

Section: Introductionmentioning

confidence: 98%

Activation of Cytosol Aldosterone Receptors in Rat Kidney

Hacha

Palem-Vliers

Frédéricq

1985

Archives Internationales de Physiologie et de Biochimie

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Cytosolic aldosterone-protein complexes are isolated from rat kidney slices after incubation with [3H]aldosterone and dexamethasone. Activated and unactivated forms of the complex are characterized by gel electrophoresis and hydroxyapatite chromatography after incubation at 4 degrees C and 25 degrees C respectively. It is found that the activated form reaches a maximum after 30 min at 25 degrees C and can be separated as an homogeneous peak by electrophoresis. Intermediate forms can also be identified. In the presence of 10 mM ATP, activation immediately occurs at 4 degrees C and is almost complete. In the presence of 10 mM molybdate, the activation is strongly enhanced and the increase in activated form may be about fifteen-fold whether molybdate is added during kidney homogenization or just before incubation at 25 degrees C. On the other hand molybdate reduces to one third the binding of the aldosterone-receptor complexes to nuclei. In the presence of the steroid RU 26988 which is a pure glucocorticoid, experiments done on aldosterone-receptors complexes and their binding to nuclei are confirmed. This proves that aldosterone is specific for mineralocorticoid sites. The general pattern of the mineralocorticoid receptor activation is discussed and its resemblance to the case of other steroid hormones is emphasized.

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Effect of 6-dehydro-doca and 6-dehydro-9αfluorocortisol acetate on the excretion of sodium and potassium in the rat

Genard

Palem-Vliers

1985

Journal of Steroid Biochemistry

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Physico-chemical characterization of cytosol and nuclear mineralocorticoid receptors in rat kidney

Cited by 8 publications

References 14 publications

Effect of various 6-dehydro-corticosteroids, 9,11 -dehydro-DOCA and 9α-fluoro-DOCA on the fluxes of sodium and potassium

Effect of various 6-dehydro-corticosteroids, 9,11 -dehydro-DOCA and 9α-fluoro-DOCA on the fluxes of sodium and potassium

Activation of Cytosol Aldosterone Receptors in Rat Kidney

Effect of 6-dehydro-doca and 6-dehydro-9αfluorocortisol acetate on the excretion of sodium and potassium in the rat

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