Decreased insulin secretory capacity and normal pancreatic B-cell glucose sensitivity in non-obese patients with NIDDM.
We investigated the dose-response characteristics of glucose-induced insulin release and the influence of hyperglycaemia on arginine-induced insulin secretion in eight non-obese subjects with NIDDM and in eight non-diabetic volunteers. Plasma C-peptide levels, achieved during 60 min hyperglycaemic clamps with and without the infusion of a primed continuous infusion of arginine (infusion rate 15 mg kg-1 min-1) during the last 30 min, were analysed with a modified Michaelis-Menten equation. The insulin secretory capacity (Vmax) for glucose-stimulated insulin release showed a trend towards a negative correlation with the fasting blood glucose in the NIDDM subjects (r = 0.68, P = 0.6); it was lower than the Vmax of non-diabetic controls (2.2 +/- 0.2 vs 4.2 +/- 0.4 nmol l-1 respectively; P less than 0.001). The ED50 (half maximal stimulating blood glucose concentration) of the second-phase glucose-stimulated insulin release (determined from the plasma C-peptide levels at 60 min) was not significantly different from the ED50 of the controls (11.9 +/- 0.8 vs 13.3 +/- 1.9 mmol l-1 respectively; P greater than 0.2). Combined glucose-arginine stimulation significantly increased insulin release. The Vmax for both phases were significantly lower in NIDDM patients than in controls (2.3 +/- 0.2 vs 5.0 +/- 0.9 and 3.8 +/- 0.5 vs 8.5 +/- 0.9 nmol l-1 respectively; P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Van Haeften
T W
TW
Department of Endocrinology, Free University Hospital, Amsterdam, The Netherlands.
Van Maarschalkerweerd
W W
WW
Gerich
J E
JE
Van der Veen
E A
EA
D000328:Adult; D000368:Aged; D001120:Arginine; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005947:Glucose; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D008297:Male; D008875:Middle Aged
D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin; D001120:Arginine; D005947:Glucose