Biomaterial Database

Short-term effects of aldosterone and dexamethasone on Na-K-ATPase along the rabbit nephron. 1983

G El Mernissi, and A Doucet

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 whether 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 micrograms/kg) but not by aldosterone (up to 10 micrograms/kg). In the cortical (CCT) and medullary (MCT) collecting tubule the enzyme activity decreased by 75% after adrenalectomy but in contrast with the MAL and the DCT, these two segments were sensitive to both dexamethasone (100 micrograms/kg) and aldosterone (10 micrograms/kg) and recovered their activities within 3 h after the hormone injection. These effects were not additive. Spironolactone (100 micrograms/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.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D009399	Nephrons	The functional units of the kidney, consisting of the glomerulus and the attached tubule.	Nephron
D011817	Rabbits	A burrowing plant-eating mammal with hind limbs that are longer than its fore limbs. It belongs to the family Leporidae of the order Lagomorpha, and in contrast to hares, possesses 22 instead of 24 pairs of chromosomes.	Belgian Hare,New Zealand Rabbit,New Zealand Rabbits,New Zealand White Rabbit,Rabbit,Rabbit, Domestic,Chinchilla Rabbits,NZW Rabbits,New Zealand White Rabbits,Oryctolagus cuniculus,Chinchilla Rabbit,Domestic Rabbit,Domestic Rabbits,Hare, Belgian,NZW Rabbit,Rabbit, Chinchilla,Rabbit, NZW,Rabbit, New Zealand,Rabbits, Chinchilla,Rabbits, Domestic,Rabbits, NZW,Rabbits, New Zealand,Zealand Rabbit, New,Zealand Rabbits, New,cuniculus, Oryctolagus
D003907	Dexamethasone	An anti-inflammatory 9-fluoro-glucocorticoid.	Hexadecadrol,Decaject,Decaject-L.A.,Decameth,Decaspray,Dexasone,Dexpak,Hexadrol,Maxidex,Methylfluorprednisolone,Millicorten,Oradexon,Decaject L.A.
D000251	Adenosine Triphosphatases	A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.	ATPases,Adenosinetriphosphatase,ATPase,ATPase, DNA-Dependent,Adenosine Triphosphatase,DNA-Dependent ATPase,DNA-Dependent Adenosinetriphosphatases,ATPase, DNA Dependent,Adenosinetriphosphatases, DNA-Dependent,DNA Dependent ATPase,DNA Dependent Adenosinetriphosphatases,Triphosphatase, Adenosine
D000254	Sodium-Potassium-Exchanging ATPase	An enzyme that catalyzes the active transport system of sodium and potassium ions across the cell wall. Sodium and potassium ions are closely coupled with membrane ATPase which undergoes phosphorylation and dephosphorylation, thereby providing energy for transport of these ions against concentration gradients.	ATPase, Sodium, Potassium,Adenosinetriphosphatase, Sodium, Potassium,Na(+)-K(+)-Exchanging ATPase,Na(+)-K(+)-Transporting ATPase,Potassium Pump,Sodium Pump,Sodium, Potassium ATPase,Sodium, Potassium Adenosinetriphosphatase,Sodium-Potassium Pump,Adenosine Triphosphatase, Sodium, Potassium,Na(+) K(+)-Transporting ATPase,Sodium, Potassium Adenosine Triphosphatase,ATPase Sodium, Potassium,ATPase, Sodium-Potassium-Exchanging,Adenosinetriphosphatase Sodium, Potassium,Pump, Potassium,Pump, Sodium,Pump, Sodium-Potassium,Sodium Potassium Exchanging ATPase,Sodium Potassium Pump
D000315	Adrenalectomy	Excision of one or both adrenal glands. (From Dorland, 28th ed)	Adrenalectomies
D000450	Aldosterone	A hormone secreted by the ADRENAL CORTEX that regulates electrolyte and water balance by increasing the renal retention of sodium and the excretion of potassium.	Aldosterone, (+-)-Isomer,Aldosterone, (11 beta,17 alpha)-Isomer
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013148	Spironolactone	A potassium sparing diuretic that acts by antagonism of aldosterone in the distal renal tubules. It is used mainly in the treatment of refractory edema in patients with congestive heart failure, nephrotic syndrome, or hepatic cirrhosis. Its effects on the endocrine system are utilized in the treatments of hirsutism and acne but they can lead to adverse effects. (From Martindale, The Extra Pharmacopoeia, 30th ed, p827)	Spirolactone,Aldactone,Aldactone A,Aquareduct,Duraspiron,Espironolactona Alter,Espironolactona Mundogen,Flumach,Frumikal,Jenaspiron,Novo-Spiroton,Practon,SC-9420,Spiractin,Spiro L.U.T.,Spiro Von Ct,Spirobeta,Spirogamma,Spirolang,Spirono-Isis,Spironone,Spirospare,Veroshpiron,Verospiron,Verospirone,Ct, Spiro Von,Novo Spiroton,NovoSpiroton,SC 9420,SC9420,Spirono Isis,Von Ct, Spiro