Differential effect of amino acid infusion route on net hepatic glucose uptake in the dog

Concomitant portal infusion of gluconeogenic amino acids (GNGAA) and glucos e significantly reduces net hepatic glucose uptake (NHGU), in comparison wi th NHGU during portal infusion of glucose alone. To determine whether this effect on NHGU is specific to the portal route of GNGAA delivery, somatosta tin, intraportal insulin (3-fold basal) and glucagon (basal), and intraport al glucose (to increase the hepatic glucose load by similar to 50%) were in fused for 240 min. GNGAA were infused peripherally into a group of dogs (Pe AA), at a rate to match the hepatic GNGAA load in a group of dogs that were given the same GNGAA mixture intraportally (PoAA) at 7.6 mu mol.kg(-1).min (-1) (9). The arterial blood glucose concentrations and hepatic glucose loa ds were the same in the two groups, but NHGU (-0.9 +/- 0.2 PoAA and -2.1 +/ - 0.5 mg.kg(-1).min(-1) in PeAA, P < 0.05) and net hepatic fractional extra ction of glucose (2.6 +/- 0.7% in PoAA vs. 5.9 +/- 1.4% in PeAA, P < 0.05) differed. Neither the hepatic loads nor the net hepatic uptakes of GNGAA we re significantly different in the two groups. Net hepatic glycogen synthesi s was similar to 2.5-fold greater in PeAA than PoAA (P < 0.05). Intraportal , but not peripheral, amino acid infusion suppresses NHGU and net hepatic g lycogen synthesis in response to intraportal glucose infusion.