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Role of phosphatidy...
Role of phosphatidylinositol 3-kinase gamma in the beta-cell: Interactions with glucagon-like peptide-1
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Li, LX (författare)
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- MacDonald, Patrick (författare)
- Lund University,Lunds universitet,Institutionen för experimentell medicinsk vetenskap,Medicinska fakulteten,Department of Experimental Medical Science,Faculty of Medicine
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Ahn, DS (författare)
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Oudit, GY (författare)
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Backx, PH (författare)
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Brubaker, PL (författare)
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(creator_code:org_t)
- The Endocrine Society, 2006
- 2006
- Engelska.
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Ingår i: Endocrinology. - : The Endocrine Society. - 0013-7227 .- 1945-7170. ; 147:7, s. 3318-3325
- Relaterad länk:
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http://dx.doi.org/10... (free)
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https://academic.oup...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Glucagon-like peptide-1 (GLP-1) increases beta-cell function and growth through protein kinase A- and phosphatidylinositol-3-kinase (PI3-K)/protein kinase B, respectively. GLP-1 acts via a G protein-coupled receptor, and PI3-K gamma is known to be activated by G(beta gamma). Therefore, the role of PI3-K gamma in the chronic effects of GLP-1 on the beta-cell was investigated using PI3-K gamma knockout (KO) mice treated with the GLP-1 receptor agonist, exendin-4 (Ex4; 1 nmol/kg sc every 24 h for 14 d). In vivo, glucose and insulin responses were similar in PBS- and Ex4-treated KO and wild-type (WT) mice. However, glucose-stimulated insulin secretion was markedly impaired in islets from PBS-KO mice (P < 0.05), and this was partially normalized by chronic Ex4 treatment (P < 0.05). In contrast, insulin content was increased in PBS- KO islets, and this was paradoxically decreased by Ex4 treatment, compared with the stimulatory effect of Ex4 on WT islets (P < 0.05-0.01). Transfection of INS-1E beta-cells with small interferingRNAfor PI3-K gamma similarly decreased glucose-stimulated insulin secretion (P < 0.01) and increased insulin content. Basal values for beta-cell mass, islet number and proliferation, glucose transporter 2, glucokinase, and insulin receptor substrate-2 were increased in PBS- KO mice (P < 0.05-0.001) and, although they were increased by Ex4 treatment of WT animals (P < 0.05), they were decreased in Ex4-KO mice (P < 0.05-0.01). These findings indicate that PI3-K gamma deficiency impairs insulin secretion, resulting in compensatory islet growth to maintain normoglycemia. Chronic Ex4 treatment normalizes the secretory defect, thereby relieving the pressure for expansion of beta-cell mass. These studies reveal a new role for PI3-K gamma as a positive regulator of insulin secretion, and reinforce the importance of GLP-1 for the maintenance of normal beta-cell function.
Ämnesord
- MEDICIN OCH HÄLSOVETENSKAP -- Klinisk medicin -- Endokrinologi och diabetes (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Clinical Medicine -- Endocrinology and Diabetes (hsv//eng)
Publikations- och innehållstyp
- art (ämneskategori)
- ref (ämneskategori)
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