RESUMO
In order to investigate the central effect of alarin on glucose uptake, we administered alarin and/ or its inhibitor, ala6-25Cys into the cerebral ventricles of the type 2 diabetic rats. Then the relative parameters about glucose uptake in skeletal muscles were measured. We found that central treatment with alarin significantly increased the food intake, body weight and glucose infusion rates in hyperinsulinemic euglycemic clamp tests of the animals. Besides, the treatment also enhanced 2-deoxy-[3H]-D-glucose uptake, vesicle-associated membrane protein 2 contents, glucose transporter 4 protein and mRNA expression, as well as pAktThr308, pAktSer473 and total Akt levels in muscle cells, but reduced plasma glucose and insulin levels of the rats. All of the alarin-inducing events may be antagonised by central injection of ala6-25Cys. These results suggest that central administration of alarin stimulates glucose uptake mediated by activation of Akt signal pathway in type 2 diabetic animals.
Assuntos
Diabetes Mellitus Experimental/metabolismo , Peptídeo Semelhante a Galanina/farmacologia , Glucose/metabolismo , Músculo Esquelético/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Linhagem Celular , Ingestão de Alimentos/efeitos dos fármacos , Transportador de Glucose Tipo 4/metabolismo , Injeções Intraventriculares , Insulina/sangue , Camundongos , Músculo Esquelético/metabolismo , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , RatosRESUMO
Pold2 is a subunit of the DNA polymerase δ complex, encoding a protein involved in DNA replication and repair. In this study, using a yeast two-hybrid screening technique and the common cDNA fragment of the mouse PIAS2 as a bait, Pold2 was found to interact with PIAS2. A direct interaction between Pold2 and PIAS2 was confirmed by direct yeast two-hybrid. In vivo evidence of Pold2 association with PIAS2 was obtained by co-immunoprecipitation using HEK-293 cells. Subcellular localization studies demonstrated that Pold2 and PIAS2 were partially co-localized in mammalian cells. Collectively, our results suggest that Pold2 interacts under physiological conditions with PIAS2.
Assuntos
DNA Polimerase III/metabolismo , Proteínas Inibidoras de STAT Ativados/metabolismo , Animais , DNA Polimerase III/análise , DNA Polimerase III/genética , DNA Complementar/genética , Células HEK293 , Células HeLa , Humanos , Camundongos , Proteínas Inibidoras de STAT Ativados/análise , Proteínas Inibidoras de STAT Ativados/genética , Mapeamento de Interação de Proteínas , Fator de Transcrição STAT2/metabolismo , Transfecção , Técnicas do Sistema de Duplo-HíbridoRESUMO
The aim of this study is to investigate whether galanin (GAL) central receptors are involved in regulation of insulin resistance. To test it, a GAL antagonist, M35 was intracerebroventricularly administrated in trained type 2 diabetic rats. The euglycemic-hyperinsulinemic clamp test was conducted for an index of glucose infusion rates. The epididymal fat pads were processed for determination of glucose uptake and Glucose Transporter 4 (GLUT4) amounts. The Gal mRNA expression levels in hypothalamus were quantitatively assessed too. We found an inhibitory effect of M35 on glucose uptake into adipocytes, Gal mRNA expression levels in hypothalamus, glucose infusion rates in the clamp test and GLUT4 concentration in plasma membranes and total cell membranes of adipocytes. The ratios of GLUT4 contents of the former to the latter in M35 groups were lower. These results suggest a facilitating role for GAL on GLUT4 translocation and insulin sensitivity via its central receptors in rats.
Assuntos
Adipócitos/metabolismo , Bradicinina/análogos & derivados , Diabetes Mellitus Tipo 2/patologia , Galanina/antagonistas & inibidores , Resistência à Insulina , Fragmentos de Peptídeos/administração & dosagem , Fragmentos de Peptídeos/farmacologia , Condicionamento Físico Animal , Adipócitos/efeitos dos fármacos , Adipócitos/patologia , Animais , Glicemia/metabolismo , Peso Corporal/efeitos dos fármacos , Bradicinina/administração & dosagem , Bradicinina/farmacologia , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Colesterol/sangue , Desoxiglucose/metabolismo , Diabetes Mellitus Tipo 2/sangue , Jejum/sangue , Galanina/administração & dosagem , Galanina/genética , Galanina/metabolismo , Galanina/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Técnica Clamp de Glucose , Transportador de Glucose Tipo 4/metabolismo , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Injeções Intraventriculares , Insulina/sangue , Masculino , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Triglicerídeos/sangueRESUMO
Although galanin has been shown to increase insulin sensitivity in skeletal muscle of rats, there is no literature available about the effect of galanin on Glucose Transporter 4 (GLUT4) translocation from intracellular membrane pools to plasma membranes in adipocytes of type 2 diabetic rats. In the present study M35, a galanin antagonist was used to elucidate whether exercise-induced galanin release increased GLUT4 translocation in adipocytes of streptozotocin-induced diabetic rats. The present findings showed that plasma galanin levels after swimming training in all four trained groups were higher compared with each sedentary control. M35 treatment had an inhibitory effect on glucose infusion rates in the euglycemic-hyperinsulinemic clamp test and GLUT4 mRNA expression levels in adipocytes. Moreover, M35 treatment reduced GLUT4 concentration in both plasma membranes and total cell membranes. The ratios of GLUT4 contents in plasma membranes to total cell membranes in four drug groups were lower compared with each control. These data demonstrate a beneficial role of endogenous galanin to transfer GLUT4 from internal stores to plasma membranes in adipocytes of type 2 diabetic rats. Galanin plays a significant role in regulation of glucose metabolic homeostasis and is an important hormone relative to diabetes.