Blood flow rate and cellular influx of glucose and arginine in mouse liver in vivo

Publisher Website
Google Scholar
Abstract
Influx and washout of 3H-water was studied in mouse liver: the maximal fractional extraction was estimated to be 0.90, the half time of washout 11s, the rate constant of washout 3.6 .+-. 0.3 min-1 and portal blood flow estimated to be 3.7 ml .cntdot. min-1 .cntdot. g-1. The influx of 14C-labeled glucose and arginine was studied by tissue analysis after a single (portal vein) injection of 3 isotope-labeled compounds. Liver uptake of glucose or arginine was expressed relative to the clearance of 3H-water. EDTA labeled with 113mIn served as an extravascular space marker identifying that portion of the isotopes remaining in the hepatic capillary and interstitial spaces. Subtraction of this amount provides an estimation of the cellular liver uptake. The liver optimally removes about 1/10 of the arginine from the portal vein by a carrier-mediated process (Km = 3.4 .+-. 1.4 mM, Vmax = 1.2 .+-. 0.1 .mu.mol .times. min-1 .cntdot. g-1). More than 50% of the portal glucose may be unindirectionally cleared by the liver under optimal conditions, and the transport kinetics (Km = 262 .+-. 71 mM; Vmax = 310 .+-. 25 .mu.mol .cntdot. min-1 .cntdot. g-1) indicate a similarly low-affinity high-capacity system. A significant increase in liver arginine uptake was observed in preliminary examinations of schistosome-infected mice, emphasizing the method applicability to pathophysiological studies.