Fasting-induced dissociation of cationic and secretory events in pancreatic islets

Cell Biochemistry and Function
Angelo Rafael CarpinelliW J Malaisse

Abstract

In pancreatic islets removed from 48 h-fasted rats, as distinct from fed animals, the release of insulin evoked by D-glucose is more severely impaired than that evoked by 2-ketoisocaproate. This decreased secretory response to D-glucose contrasts with an unimpaired cationic response to the sugar in terms of the glucose-induced decrease in both 86Rb and 45Ca outflow from pre-labelled islets. Likewise, fasting only causes a modest decrease of the secondary rise in 45Ca outflow evoked by D-glucose in islets perifused at normal Ca2+ concentration. The latter decrease appears more marked, however, if the cationic response to glucose is expressed relative to that evoked by 2-ketoisocaproate in islets removed from rats in the same nutritional state. It is concluded that, in the process of nutrient-stimulated insulin release, neither the decrease in K+ conductance (inhibition of 86Rb outflow) nor the sequestration of Ca2+ by intracellular organelles and/or direct inhibition of Ca2+ outward transport (decrease in 45Ca outflow) represent the sole determinant(s) of the subsequent gating of Ca2+ channels (secondary rise in 45Ca efflux).

References

Apr 1, 1979·Metabolism: Clinical and Experimental·W J MalaisseJ C Hutton
Oct 1, 1967·The American Journal of Physiology·W J MalaisseP H Wright
Sep 1, 1982·The American Journal of Physiology·R J Stark, J O'Doherty
Mar 15, 1984·Biochemical and Biophysical Research Communications·M H GiroixW J Malaisse
Jan 1, 1982·The American Journal of Physiology·C A Colton, J S Colton
Feb 1, 1980·Molecular and Cellular Endocrinology·Angelo Rafael Carpinelli, W J Malaisse
Jun 1, 1981·The Journal of Physiology·Angelo Rafael Carpinelli, W J Malaisse

Citations

Jan 1, 1987·Acta diabetologica latina·F Malaisse-LagaeW J Malaisse
May 1, 1989·Physiology & Behavior·A Santos JúniorAngelo Rafael Carpinelli
Mar 7, 2014·The Journal of Endocrinology·Ananda MaltaPaulo Cezar de Freitas Mathias
Oct 1, 1991·Radiotherapy and Oncology : Journal of the European Society for Therapeutic Radiology and Oncology·Y SarriR Gomis
Sep 1, 1988·Journal of Endocrinological Investigation·B BillaudelW J Malaisse

Related Concepts

alpha-ketoisocaproic acid, sodium salt
Calcium Radioisotopes
Cations, Divalent
Egtazic Acid Sodium Salt
Fasting
Glucose, (beta-D)-Isomer
Novolin
Islets of Langerhans
Keto Acids
Radioisotopes

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