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Dose-Response Characteristics for Arginine-Stimulated Insulin Secretion in Man and Influence of Hyperglycemia *

1989; Oxford University Press; Volume: 69; Issue: 5 Linguagem: Inglês

10.1210/jcem-69-5-1059

1945-7197

Timon W. van Haeften, G. A. Voetberg, John E. Gerich, E. A. v. d. Veen,

Diabetes and associated disorders

To test the hypothesis that glucose only affects the responsiveness (maximum velocity) of the β-cell to arginine without changing the sensitivity (ED50) of the β-cell to arginine, we investigated the influence of hyperglycemia on the responsiveness and sensitivity of arginine-induced insulin secretion in eight healthy male volunteers. Plasma C-peptide and insulin levels achieved during infusions of five doses of arginine (30 min) with and without a 60-min hyperglycemic clamp (17 mmol/L) were analyzed using a modified Michaelis-Menten equation. At euglycemia, the ED50 (half-maximally stimulating serum arginine concentration) was significantly less for first phase than for second phase plasma C-peptide secretion (0.7 ± 0.1 vs. 2.7 ± 0.4 mmol/L; P < 0.002). Hyperglycemia significantly increased arginine-induced insulin secretion at all arginine infusion rates (P < 0.01) without significantly altering the ED50 for either phase. We conclude 1) that the regulation of arginine-induced insulin secretion differs between both phases of insulin secretion, and 2) that a 1-h infusion with glucose significantly potentiates arginine-induced insulin secretion without influencing the difference in regulation of both phases of arginine-induced insulin secretion, supporting the validity of the use of arginine as a secretagogue in studies involving hyperglycemia.