N. Coutry et al., SYNERGISTIC ACTION OF VASOPRESSIN AND ALDOSTERONE ON BASOLATERAL NA-K+-ATPASE IN THE CORTICAL COLLECTING DUCT(), The Journal of membrane biology, 145(1), 1995, pp. 99-106
The respective effects of aldosterone and arginine vasopressin (AVP) w
ere examined on the number of active Na+-K+-ATPase and their pumping a
ctivity in nonperfused microdissected mouse cortical collecting tubule
s (CCD) by measuring specific H-3-ouabain binding and ouabain-sensitiv
e Rb-86 uptake. In adrenalectomized (ADX) animals, incubation of CCD w
ith 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 congr
uent to 40% increase in the number of pumps. This was accompanied by a
congruent to 60-65% increase in ouabain-sensitive Rb uptake. AVP effe
ct was dose-dependent (10-(10)-10(-8) M) and was reproduced by dDAVP,
forskolin and 8-Br cAMP, indicating a V-2 pathway. It was inhibited by
amiloride 10(-5) M, and did not occur in CCD incubated in hyperosmoti
c solution, suggesting that the signal was transmitted via apical sodi
um entry and cell swelling. Finally, the AVP-dependent increase in the
number of pumps was rapid (within 5 min) and transient (<25 min). The
se results demonstrate that, in the CCD, aldosterone and AVP act syner
gistically to increase not only the Na+-K+- apical sodium entry but al
so me basolateral Na+-K+-ATPase transport capacity: AVP allows a rapid
recruitment and/or activation of an aldosterone-dependent pool of lat
ent Na+-K+-ATPase.