Signal transduction in islet hormone release: interaction of nitric oxide with basal and nutrient-induced hormone responses

Summary, in English

We examined the relation between the islet NO system and islet hormone secretion induced by either the non-glucose nutrient alpha-ketoisocaproic acid (KIC) or, in some experiments, glucose. KIC dose dependently stimulated insulin but inhibited glucagon secretion. In a medium devoid of any nutrient, the NO synthase (NOS)-inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) induced an increase in basal insulin release but a decrease in glucagon release. These effects were evident also in K+-depolarised islets. KIC-induced insulin release was increased by L-NAME. This increase was abolished in K+-depolarised islets. In contrast, glucose- induced insulin release was potentiated by L-NAME after K+ depolarisation. The intracellular NO donor hydroxylamine dose dependently inhibited KIC-stimulated insulin release and reversed KIC-induced suppression of glucagon release. Our data suggest that islet hormone secretion in a medium devoid of nutrients is greatly affected by the islet NO system, whereas KIC-induced secretion is little affected. Glucose-induced insulin release, however, is accompanied by increased NOS activity, the NOS-activating signal being derived from the glycolytic-pentose shunt part of glucose metabolism. The observed NO effects on islet hormone release can proceed independently of membrane-depolarisation events.

• Författare: S Albert Salehi; Fariborz Parandeh; Ingmar Lundquist
• Avdelning/ar: Islet cell physiology
• Publiceringsår: 1998
• Språk: Engelska
• Sidor: 645-651
• Publikation/Tidskrift/Serie: Cellular Signalling
• Volym: 10
• Issue: 9
• Länkar: http://dx.doi.org/10.1016/S0898-6568(98)00005-9
• Dokumenttyp: Artikel i tidskrift
• Förlag: Elsevier
• Ämne: Microbiology
• Status: Published
• Forskningsgrupp: Islet cell physiology
• ISBN/ISSN/Övrigt: ISSN: 1873-3913