Diabetes, Vol 34, Issue 6 541-547, Copyright © 1985 by American Diabetes Association
Abnormal glucose modulation of islet A- and B-cell responses to arginine in non-insulin-dependent diabetes mellitus
GD Dimitriadis, GB Pehling and JE Gerich
To assess the normality of islet A- and B-cell responses to a nonglucose
secretogogue as well as the modulating effect of glucose in NIDDM, we
examined plasma C-peptide and glucagon responses to arginine in eight
patients with NIDDM and in six age- and weight-matched nondiabetic
volunteers under conditions of identical hypoglycemia (approximately 70
mg/dl), euglycemia (94 mg/dl), and hyperglycemia (approximately 190 mg/dl).
Plasma C-peptide responses to glucose and to arginine in the diabetic
subjects were both significantly reduced at all glucose concentrations
studied (P less than 0.01-0.005). The modulating effect of glucose on both
islet A- and B-cell responses (slope of relation between plasma C-peptide
or glucagon response versus plasma glucose concentration) was reduced
greater than 80% in the diabetic subjects (P less than 0.01). We conclude
that islet A- and B-cell responses to nonglucose secretogogues are abnormal
in patients with NIDDM and that this may result from a functional defect in
the modulating effect of glucose on insulin and glucagon secretion, which
in some patients may be compensated for by hyperglycemia.