Multisite control of insulin release by glucose.
Glucose controls insulin release by beta-cells at two sites at least. By controlling the membrane potential, it controls the influx of Ca2+ and the rise in cytoplasmic Ca2+ which triggers exocytosis. At this level, the principal targets of glucose are the K(+)-ATP channels whose activity may be modulated by changes in the ATP/ADP ratio. A second, newly identified, mechanism of regulation is independent of changes in beta-cell membrane potential and of changes in Cai2+. It is not sufficient to induce insulin release, but serves to increase the response. This appears to be achieved through an amplification of the effectiveness of Cai2+ on the secretory process and may also depend on the changes in energy state of beta-cells.
Henquin
J C
JC
Unité d'Endocrinologie et Métabolisme, University of Louvain, Faculty of Medicine, Bruxelles, Belgium.
Gembal
M
M
Detimary
P
P
Gao
Z Y
ZY
Warnotte
C
C
Gilon
P
P
D000818:Animals; D005947:Glucose / Q000494:pharmacology*; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D008564:Membrane Potentials / Q000502:physiology
D007328:Insulin; D005947:Glucose