Abstract
Both glucocorticoids and mineralcorticoids stimulate the renal Na−K-ATPase. However, the exact site of their respective action is not precisely determined and it is still unknown wheter these effects are cumulative or not.
We studied the effects of dexamethasone and aldosterone on Na−K-ATPase activity in microdissected nephron segments from adrenalectomized rabbits. In proximal convoluted tubule (PCT) the enzyme activity was altered neither by adrenalectomy nor by any steroid replacement. In the medullary thick ascending limb of the loop of Henle (MAL) and the distal convoluted tubule (DCT), Na−K-ATPase activity decreased by 40% after adrenalectomy, and was restored to control level three hours after administration of dexamethasone (100 μg/kg) but not by aldosterone (up to 10 μg/kg). In the cortical (CCT) and medullary (MCT) collecting tubule the enzyme activity decreased by 75% after adrenalcetomy but in contrast with the MAL and the DCT, these two segments were sensitive to both dexamethasone (100 μg/kg) and aldosterone (10 μg/kg) and recovered their activities within 3 h after the hormone injection. These effects were not additive. Spironolactone (100 μg/kg) abolished the action of each of the two hormones on the CCT and MCT. In contrast, spironolactone did not curtail the effect of dexamethasone on MAL and DCT. These results indicate that whereas glucocorticoid action is localized in MAL, DCT, CCT and MCT, the mineralocorticoid effect is restricted to the CCT and MCT exclusively. They also suggest that, in the CCT and MCT, the two types of hormones share the same receptors.
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References
Charney AN, Silva P, Besarab A, Epstein FH (1974) Separate effects of aldosterone, DOCA, and methylprednisolone on renal Na−K-ATPase. Am J Physiol 227: 345–350
Chignell CF, Titus E (1966) Effect of adrenal steroids on a Na+-and K+-requiring adenosine triphosphatase from rat kidney. J Biol Chem 241: 5083–5089
Doucet A, Katz AI, Morel F (1979) Determination of Na−K-ATPase activity in single segments of the mammalian nephron. Am J Physiol 237: F105-F113
Doucet A, Katz AI (1981) Short-term effect of aldosterone on Na−K-ATPase in single nephron segments. Am J Physiol 241: F273-F278
Doucet A, Katz AI (1981) Mineralocorticoid receptors along the nephron:3H-aldosterone binding in rabbit tubules. Am J Physiol 241: F605-F611
El Mernissi G, Doucet A (1983) Short-term effects of aldosterone on renal sodium transport and tubular Na−K-ATPase in the rat. Pflügers Arch 399: 139–146
Farman N, Vandewalle A, Bonvalet JP (1982) Aldosterone binding in isolated tubule. II. An autoradiographic study of concentration dependency in the rabbit nephron. Am J Physiol 242: F69-F77
Hendler ED, Torretti J, Kupor L, Epstein FH (1972) Effects of adrenalectomy and hormone replacement on Na−K-ATPase in renal tissue. Am J Physiol 222: 754–760
Horster M, Schmid H, Schmidt U (1980) Aldosterone in vitro restores nephron Na−K-ATPase of distal segments from adrenalectomized rabbits. Pflügers Arch 384: 203–206
Jørgensen PL (1968) Regulation of the (Na++K+)-activated ATP hydrolyzing enzyme system in rat kidney. I. The effect of adrenalectomy and the supply of sodium on the enzyme system. Biochim Biophys Acta 151: 212–224
Jørgensen PL, (1972) The role of aldosterone in the regulation of (Na++K+)-ATPase in rat kidney. J Steroid Biochem 3: 181–191
Katz AI, Doucet A, Morel F (1979) Na−K-ATPase activity along the rabbit, rat, and mouse nephron. Am J Physiol 237: F114-F120
Katz AI, Lee SMK, Chekal MA (1982) Corticosterone binding along the rat nephron. In: Morel F (ed) Biochemistry of kidney functions. Elsevier, Amsterdam, pp 277–283
Landon EJ, Jazab N, Forte L (1966) Aldosterone and sodium-potassium-dependent ATPase activity of rat kidney membranes. Am J Physiol 211: 1050–1056
Petty KJ, Kokko JP, Marver D (1981) Secondary effect of aldosterone on Na−K-ATPase activity in the rabbit cortical collecting tubule. J Clin Invest 68: 1514–1521
Pham Huu Trung MT, Corvol P (1974) Direct radioimmunoassay of plasma aldosterone. Steroid 24: 587
Rayson BM, Edelman IS (1982) Glucocorticoid stimulation of Na−K-ATPase in superfused distal segments of kidney tubules in vitro. Am J Physiol 243: F463-F470
Rodriguez HJ, Sinha SK, Starling J, Klahr S (1981) Regulation of renal Na+−K+-ATPase in the rat by adrenal steroids. Am J Physiol 241: F186-F195
Schmidt U, Dubach UC (1971) Sensitivity of Na−K-adenosine triphosphatase activity in various structures of the rat nephron: studies with adrenalectomy. Eur J Clin Invest 1: 307–312
Schmidt U, Schmid J, Schmid H, Dubach U (1975) Sodium and potassium activated ATPase: A possible target of aldosterone. J Clin Invest 55: 655–660
Sinha SK, Rodriguez HJ, Hogan WC, Klahr S (1981) Mechanisms of activation of renal (Na++K+)-ATPase in the rat. Effects of acute and chronic administration of dexamethasone. Biochim Biophys Acta 641: 20–35
Vandewalle A, Farman A, Bencsath P, Bonvalet JP (1981) Aldosterone binding along the rabbit nephron: An autoradiographic study on isolated tubules. Am J Physiol 240: F172-F179
Westenfelder C, Arevalo GJ, Baranowski RL, Kurtzman NA, Katz AI (1977) Relationship between mineralocorticoids and renal Na+−K+-ATPase: Sodium reabsorption. Am J Physiol 233: F593-F599
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Mernissi, G.E., Doucet, A. Short-term effects of aldosterone and dexamethasone on Na−K-ATPase along the rabbit nephron. Pflugers Arch. 399, 147–151 (1983). https://doi.org/10.1007/BF00663911
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DOI: https://doi.org/10.1007/BF00663911