A portal-arterial glucose concentration gradient as a signal for an insulin-dependent net glucose uptake in perfused rat liver.
Since in the usual perfusion of isolated rat liver via the portal vein an insulin-dependent increase of hepatic glucose uptake could not be demonstrated, the possibility was considered that hepatic glucose uptake might not be a function of the absolute concentration of this substrate but of its concentration gradient between the portal vein and the hepatic artery. Therefore a new method was established for the simultaneous perfusion of isolated rat liver via both the hepatic artery (20-35% flow) and the portal vein (80-65% flow). When glucose was offered in a concentration gradient, 9.5 mM in the portal vein and 6 mM in the hepatic artery, insulin given via both vessels caused a shift from net glucose release to uptake. This insulin-dependent shift was not observed when glucose was offered without a gradient or with an inverse gradient, 6 mM in the portal vein and 9.5 mM in the hepatic artery. Using a portal-arterial glucose gradient as a signal the liver might be able to differentiate between endogenous and exogenous glucose.
D000818:Animals; D001786:Blood Glucose / Q000032:analysis*; D006499:Hepatic Artery; D007328:Insulin / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism*; D008297:Male; D010477:Perfusion; D011169:Portal Vein; D051381:Rats; D011919:Rats, Inbred Strains
D001786:Blood Glucose; D007328:Insulin