Dual action of adiponectin on insulin secretion in insulin-resistant mice.
Adiponectin is secreted by adipocytes and has been implicated as a mediator of insulin sensitivity. In this study, the acute effects of adiponectin on islets isolated from normal or diet-induced insulin resistant mice were examined. In normal islets, adiponectin (5 microg/ml) had no significant effect on insulin secretion. In contrast, in islets from mice rendered insulin resistant by high-fat feeding, adiponectin inhibited insulin secretion at 2.8 mM (P < 0.01) but augmented insulin secretion at 16.7 mM glucose (P < 0.05). The augmentation of glucose-stimulated insulin secretion by adiponectin was accompanied by increased glucose oxidation (P < 0.005), but without any significant effect on palmitate oxidation or the islet ATP/ADP ratio. Furthermore, RT-PCR revealed the expression of the adiponectin receptor AdipoR1 mRNA in mouse islets, however, with no difference in the degree of expression level between the two feeding groups. The results thus uncover a potential dual role for adiponectin to modify insulin secretion in insulin resistance.
Winzell
Maria Sörhede
MS
Department of Medicine, Lund University, Lund, Sweden. Maria.Sorhede_Winzell@med.lu.se
Nogueiras
Rubén
R
Dieguez
Carlos
C
Ahrén
Bo
B
D052242:Adiponectin; D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D005260:Female; D005947:Glucose / Q000494:pharmacology; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance / Q000502:physiology*; D000078790:Insulin Secretion; D036341:Intercellular Signaling Peptides and Proteins; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D008099:Liver / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D018482:Muscle, Skeletal / Q000502:physiology; D011506:Proteins / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D054419:Receptors, Adiponectin; D011956:Receptors, Cell Surface / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D052242:Adiponectin; D017931:DNA Primers; D007328:Insulin; D036341:Intercellular Signaling Peptides and Proteins; D011506:Proteins; D012333:RNA, Messenger; D054419:Receptors, Adiponectin; D011956:Receptors, Cell Surface; C475419:adiponectin receptor 1, mouse; C475421:adiponectin receptor 2, mouse; D005947:Glucose