Effect of difference in glucose infusion rate on quantification of hepatic glucose production

This study was carried out to determine whether hepatic glucose production (HGP) could be suppressed in normal subjects by infusing different amounts of glucose, in the absence of significant changes in steady state plasma glucose (SSPG) or insulin (SSPI) concentrations. Consequently, subjects were infused with somatostatin (215 nmol/h), insulin (28.7 pmol/m2.min), and amounts of glucose varying from 0-200 mumol/m2.min in the absence or presence of glucagon (5.2 pmol/m2.min). SSPI concentrations were constant (60-70 pmol/L) during these studies, and values for the total glucose appearance rate (glucose infusion rate plus HGP) and SSPG did not vary significantly as a function of the rate of exogenous glucose infusion. However, values for HGP fell in response to increases in glucose infusion rate and could be suppressed to approximately 50% of the original value despite the fact that SSPG, SSPI, and glucose appearance rate did not change significantly. These data indicate that HGP can be regulated by varying the rate of exogenous glucose infusion during glucose clamp studies.