title: Modulation of Na-K-ATPase activity in the mouse medullary thick ascending limb of Henle. Effects of mineralocorticoids and sodium.
abstract: This study investigates the effect of variations in mineralocorticoid as well as cell sodium delivery and uptake on Na-K-ATPase activity in the mouse medullary thick ascending limb of Henle (mTALH). Pharmacologic doses of the mineralocorticoid deoxycorticosterone acetate (DOCA) resulted in a 28% increase of Na-K-ATPase activity. Furosemide-induced inhibition of sodium uptake by the mTALH cell also resulted in Na-K-ATPase activity reduction (45%). Sodium deprivation did not cause a clear change in enzyme activity, either at 3 d or 2 wk, likely reflecting the result of the opposing influences of decreased sodium delivery and increased endogenous aldosterone. Finally, the behavior of Na-K-ATPase activity at 3 d of sodium deprivation in the mTALH contrasted with a 60% increase in activity observed in the cortical collecting tubule, a nephron segment known to be responsive to mineralocorticoid, and this heterogeneity of response may suggest an important role for the mTALH in maintaining salt homeostasis.
authors.affiliation: Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115.
authors.forename: E B
authors.initials: EB
authors.lastname: Grossman
authors.forename: S C
authors.initials: SC
authors.lastname: Hebert
mesh_terms: D000450:Aldosterone / Q000097:blood; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D003900:Desoxycorticosterone / Q000008:administration & dosage / Q000494:pharmacology*; D004039:Diet, Sodium-Restricted; D005665:Furosemide / Q000008:administration & dosage; D007684:Kidney Tubules / Q000201:enzymology*; D007685:Kidney Tubules, Collecting / Q000201:enzymology / Q000378:metabolism; D008138:Loop of Henle / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D012964:Sodium / Q000008:administration & dosage / Q000494:pharmacology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013997:Time Factors
chemical_list: D003900:Desoxycorticosterone; D000450:Aldosterone; D005665:Furosemide; D012964:Sodium; D017301:Ca(2+) Mg(2+)-ATPase; D000254:Sodium-Potassium-Exchanging ATPase