Relationship between adrenal steroids and renal Na-K-ATPase. Effect of short-term hormone administration on the rat cortical collecting tubule.
Mineralo- and glucocorticoids stimulate renal Na-K-ATPase activity if given over a few days, but their immediate effect on the enzyme (i.e. within the time period required to alter electrolyte transport) remains controversial. We evaluated the short-term (3 h) in vivo effect of physiologic and pharmacologic doses of the natural glucocorticoid (corticosterone) and mineralocorticoid (aldosterone), and of a semisynthetic glucocorticoid (dexamethasone) on Na-K-ATPase activity in cortical collecting tubules microdissected from adrenalectomized rats. This nephron segment was chosen because it is a major target site for both classes of corticoids. Neither corticosterone (0.006, 0.6, and 5 mg/100 g body wt, IM), nor dexamethasone (5 mg/100 g body wt, IM) or aldosterone (10 micrograms and 50 micrograms, IV) altered significantly Na-K-ATPase activity in the cortical collecting tubule of these animals 3 h after administration. These results confirm our previous observations in the mouse, and suggest that the enhancing effect of corticosteroids on the renal enzyme seen after longer intervals represents a secondary phenomenon, possibly related to augmentation of the sodium load presented to the pump.
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000315:Adrenalectomy; D000450:Aldosterone / Q000494:pharmacology*; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase; D003345:Corticosterone / Q000494:pharmacology*; D003907:Dexamethasone / Q000494:pharmacology*; D007473:Ion Channels / Q000187:drug effects; D007684:Kidney Tubules / Q000201:enzymology*; D007685:Kidney Tubules, Collecting / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D007473:Ion Channels; D000450:Aldosterone; D003907:Dexamethasone; D012964:Sodium; D000251:Adenosine Triphosphatases; D017301:Ca(2+) Mg(2+)-ATPase; D000254:Sodium-Potassium-Exchanging ATPase; D003345:Corticosterone