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- Wierup, Nils, et al.
(författare)
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CART Regulates Islet Hormone Secretion and Is Expressed in the {beta}-Cells of Type 2 Diabetic Rats.
- 2006
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Ingår i: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 55:2, s. 305-311
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Tidskriftsartikel (refereegranskat)abstract
- Cocaine- and amphetamine-regulated transcript (CART) is an anorexigenic peptide widely expressed in the central, peripheral, and enteric nervous systems. CART is also expressed in endocrine cells, including β-cells during rat development and δ-cells of adult rats. We examined the effect of CART 55–102 on islet hormone secretion, using INS-1(832/13) cells and isolated rat islets. In addition, islet CART expression was examined in two rat models of type 2 diabetes: Goto-Kakizaki (GK) rats and dexamethasone (DEX)-treated rats. At high glucose, CART potentiated cAMP-enhanced insulin secretion via the cAMP/protein kinase A-dependent pathway. In the absence of cAMP-elevating agents, CART was without effect on INS-1 cells but modestly inhibited secretion of insulin, glucagon, and somatostatin from isolated islets. CART was markedly upregulated in the β-cells of both diabetes models. Thus, in DEX-treated rats, islet CART mRNA expression, and the number of CART-immunoreactive β-cells were 10-fold higher than in control rats. In GK rats, the relative number of CART-expressing β-cells was 30-fold higher than in control rats. We conclude that CART is a regulator of islet hormone secretion and that CART is upregulated in the β-cells of type 2 diabetic rats.
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