Regulation of glomerulotubular balance: flow-activated proximal tubule function

Regulation of glomerulotubular balance. III. Implication of cytosolic calcium in flow-dependent proximal tubule transport.

In the proximal tubule, axial flow (drag on brush-border microvilli) stimulates Na(+) and HCO3 (-) reabsorption by modulating both Na/H exchanger 3 (NHE3) and H-ATPase activity, a process critical to glomerulotubular balance. We have also demonstrated that blocking the angiotensin II receptor decreases baseline transport, but preserves the flow effect; dopamine leaves baseline fluxes intact, bu...

Mechanism of glomerulotubular balance. II. Regulation of proximal tubular reabsorption by tubular volume, as studied by stopped-flow microperfusion.

Atrial natriuretic factor modulates proximal glomerulotubular balance in anesthetized rats.

The extent to which the natriuretic effect of a prolonged low dose infusion of atrial natriuretic factor (30 ng/kg/min) is dependent on interference with the prevailing intrarenal actions of angiotensin II was examined before and after blockade of angiotensin production with the converting enzyme inhibitor enalaprilat (5 mg/kg). Lithium clearance was used to assess proximal tubular sodium and w...

Short-term functional adaptation of aquaporin-1 surface expression in the proximal tubule, a component of glomerulotubular balance.

Transepithelial water flow across the renal proximal tubule is mediated predominantly by aquaporin-1 (AQP1). Along this nephron segment, luminal delivery and transepithelial reabsorption are directly coupled, a phenomenon called glomerulotubular balance. We hypothesized that the surface expression of AQP1 is regulated by fluid shear stress, contributing to this effect. Consistent with this find...

Regulation of glomerulotubular balance. I. Impact of dopamine on flow-dependent transport.

In response to volume expansion, locally generated dopamine decreases proximal tubule reabsorption by reducing both Na/H-exchanger 3 (NHE3) and Na-K-ATPase activity. We have previously demonstrated that mouse proximal tubules in vitro respond to changes in luminal flow with proportional changes in Na(+) and HCO(3)(-) reabsorption and have suggested that this observation underlies glomerulotubul...