Synergistic action of vasopressin and aldosterone on basolateral Na(+)-K(+)-ATPase in the cortical collecting duct.
The respective effects of aldosterone and arginine vasopressin (AVP) were examined on the number of active Na(+)-K(+)-ATPase and their pumping activity in nonperfused microdissected mouse cortical collecting tubules (CCD) by measuring specific 3H-ouabain binding and ouabain-sensitive 86Rb uptake. In adrenalectomized (ADX) animals, incubation of CCD with AVP (10(-8) M for 5 min) had no effect on the number of pumps. In contrast, in ADX animals replete with aldosterone, AVP induced a approximately equal to 40% increase in the number of pumps. This was accompanied by a approximately equal to 60-65% increase in ouabain-sensitive Rb uptake. AVP effect was dose-dependent (10(-10)-10(-8) M) and was reproduced by dDAVP, forskolin and 8-Br cAMP, indicating a V2 pathway. It was inhibited by amiloride 10(-5) M, and did not occur in CCD incubated in hyperosmotic solution, suggesting that the signal was transmitted via apical sodium entry and cell swelling. Finally, the AVP-dependent increase in the number of pumps was rapid (within 5 min) and transient (< 25 min). These results demonstrate that, in the CCD, aldosterone and AVP act synergistically to increase not only the apical sodium entry but also the basolateral Na(+)-K(+)-ATPase transport capacity: AVP allows a rapid recruitment and/or activation of an aldosterone-dependent pool of latent Na(+)-K(+)-ATPase.
Coutry
N
N
INSERM U426, IFR "Cellules Epithéliales", Faculté X. Bichat, Paris, France.
Farman
N
N
Bonvalet
J P
JP
Blot-Chabaud
M
M
D000450:Aldosterone / Q000494:pharmacology*; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004357:Drug Synergism; D005260:Female; D017136:Ion Transport / Q000187:drug effects; D007672:Kidney Cortex / Q000378:metabolism*; D051379:Mice; D010042:Ouabain / Q000494:pharmacology; D011869:Radioligand Assay; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D014667:Vasopressins / Q000494:pharmacology*
D014667:Vasopressins; D000450:Aldosterone; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase