Glucagon-Like peptide 1(7-36) Amide Stimulates Exocytosis in Human Pancreatic β-Cells by Both Proximal and Distal Regulatory Steps in Stimulus-Secretion Coupling

摘要

The effect of glucagon-like peptide 1 (7-36) amide [GLP-1(7-36) amide] on membrane potential, whole- cell ATP-sensitive potassium channel (K_ATP) and Ca~2+ currents, cytoplasmic Ca~2+ concentration, and exocy- tosis was explored in single human β-cells. GLP-1(7-36) amide induced membrane depolarization that was asso- ciated with inhibition of whole-cell K_ATP current. In addition, GLP-1(7-36) amide (and forskolin) produced greater than fourfold potentiation of Ca~2+-dependent exocytosis. The latter effect resulted in part (40/100) from acceleration of Ca~2+ influx through voltage-depen- dent (L-type) Ca~2+ channels.