Correspondence:

Objective: Given interest in glucagon antagonism as a potential treatment of diabetes, we tested the hypothesis that glucagon, in concert with insulin, supports the postabsorptive plasma glucose concentration in humans. Research Design and Methods: Following preliminary studies which indicated that a peripheral intravenous insulin dose of 0.1 mU·kg-1·min.-1 (lower than those used previously) provides basal insulin replacement and that a glucagon dose of 1.0 ng·kg-1·min.-1 under-replaces basal glucagon, we infused the somatostatin analogue octreotide (30 ng·kg-1·min.-1) (with growth hormone replacement) over four hours in 14 healthy adults on four separate occasions to produce endogenous insulin and glucagon deficiency with: 1) saline (combined insulin and glucagon deficiency), 2) insulin replacement (isolated glucagon deficiency), 3) partial glucagon replacement (insulin and partial glucagon deficiency), and 4) insulin and partial glucagon replacement (partial glucagon deficiency). Results: During combined insulin and glucagon deficiency glucose productio