Tubuloglomerular feedback resetting in different models of acute volume expansion

Our results revealed that renal blood flow (RBF) increased during both isooncotic and hypooncotic plasma expansion by 4% of body weight (BW). Tubuloglomerular feedback (TGF) sensitivity assessed by the measurement of proximal stop-flow pressure at loop perfusion rates of 0 to 40 nl/min and RBF autoregulation were not substantially affected by this degree of volume expansion, provided plasma oncotic pressure did not change. This upward shift of the TGF response curve together with maintenance of an RBF autoregulation during plasma expansion lead to the conclusion that the TGF mechanism apparently plays a significant role in the control of glomerular hemodynamics, despite the marked vasodilation occurring during acute volume expansion.