Interaction of insulin and glucose in the control of hepatic glucose balance.

BERGMAN, RICHAI~D N., AND RICHARD J, BWCOLO. Interaction of insulin and glucose in the control of hpatic glucose balance. Am. J. Physiol. 227(6): 1314-1322. 1974.-We have examined the effect of insulin on the net balance of glucose across the isolated, bloodperfused canine liver. When perfused with blood containing glucose at 100 mg/lOO ml, the liver produced glucose at a small, constant rate. Raising the portal vein glucose level by 140 mg/lOO ml caused the liver to switch within 10 min to a constant rate of net glucose uptake. Increasing the portal vein insulin level along with the glucose did not alter the resulting steady-state net hepatic glucose balance. When infused into the portal vein for 90 min, insulin had two effects: I) it abolished the normally positive net glucose output, and 2) the liver preinfused with insulin showed a 45y0 greater change in hepatic glucose balance in response to a glucose load than when no insulin was given. It is concluded that although glucose is the more important regulator of hepatic glucose uptake during glucose infusion, insulin diminishes net hepatic glucose production and increases the dependence of hepatic glucose uptake upon the portal glucose concentration.