Open AccessThe Stimulus‐Secretion Coupling of Glucose‐Induced Insulin Release
Author(s) -
MALAISSE Willy J.,
SENER Badullash,
BOSCHERO A. Carlos,
KAWAZU Shji,
DEVIS Ghislain,
SOMERS Guido
Publication year - 1978
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1978.tb12356.x
Subject(s) - menadione , medicine , endocrinology , insulin , pancreatic islets , islet , pancreas , biology , enteroendocrine cell , chemistry , endocrine system , hormone , oxidative stress
1 Menadione (2‐methyl‐1,4‐naphoquinone) inhibits isulin release evoked in the rate endocrine pancreas by glucose or glyceraldehyde, but fails to affect the secretroy response to Ca 2+ , Ba 2+ , theophylline or gliclzide. The inhibitory effect of menadione upon glucose‐induced insulin relase is a dose‐related, rapid and reversible phenomenon, menadione and glucose acting apparently as competitive antagonists. Menadione affects both the early and talte phase of the secretory resopnse to glucose mesnadione also antagonizes in a dose‐related fashion the ability of glucose to reduce 86 Rb efflux, to provoke 86 Rb accumulation, to ecause biphasic cahnges in 45 Ca efflux and to stimulate 45 Ca net uptake in pancreatic islets. 2 It is concluded that menadione imapairs the insulinotopic action of glucose and other rutrients by impeding the remodelling of cationic fluxes normally provoked by these secretagogues in islet cells. Menadione, However, does not affect the capacity of divalent cations to activate the effector system which controls the release of secretory grnules. Meanadione may therefore represent a valuable tool to elucidate the mechanism by which glucose normally modifies the movement of cations in the pancreatic B‐cell.