Glucose regulates the release of orexin-a from the endocrine pancreas.
Diabetes
; 52(1): 111-7, 2003 Jan.
Article
em En
| MEDLINE
| ID: mdl-12502500
ABSTRACT
Orexins (hypocretins) are novel neuropeptides that appear to play a role in the regulation of energy balances. Orexin-A (OXA) increases food intake in rodents, and fasting activates OXA neurons in both the lateral hypothalamic area and gut. OXA is also found in the endocrine pancreas; however, little is known about its release or functional significance. In this study, we show that depolarizing stimuli evoke the release of OXA from rat pancreatic islets in a calcium-dependent manner. Moreover, OXA release is stimulated by low glucose (2.8 mmol/l), similar to glucagon secretion, and inhibited by high glucose (16.7 mmol/l). Fasting increases plasma OXA, supporting the idea that orexin is released in response to hypoglycemia. Cells that secrete glucagon and insulin contain OXA and both cell types express orexin receptors. OXA increases glucagon secretion and decreases glucose-stimulated insulin release from isolated islets. OXA infusion increases plasma glucagon and glucose levels and decreases plasma insulin in fasted rats. We conclude that orexin-containing islet cells, like those in the brain and gut, are glucosensitive and part of a network of glucose "sensing" cells that becomes activated when blood glucose levels fall. OXA may modulate islet hormone secretion to maintain blood glucose levels during fasting.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Neuropeptídeos
/
Proteínas de Transporte
/
Ilhotas Pancreáticas
/
Peptídeos e Proteínas de Sinalização Intracelular
/
Glucose
Limite:
Animals
Idioma:
En
Revista:
Diabetes
Ano de publicação:
2003
Tipo de documento:
Article
País de afiliação:
Estados Unidos