RESUMEN
BACKGROUND: Gap junctions between ß-cells participate in the precise regulation of insulin secretion. Adherens junctions and their associated proteins are required for the formation, function and structural maintenance of gap junctions. Increases in the number of the gap junctions between ß-cells and enhanced glucose-stimulated insulin secretion are observed during pregnancy. In contrast, protein restriction produces structural and functional alterations that result in poor insulin secretion in response to glucose. We investigated whether protein restriction during pregnancy affects the expression of mRNA and proteins involved in gap and adherens junctions in pancreatic islets. An isoenergetic low-protein diet (6% protein) was fed to non-pregnant or pregnant rats from day 1-15 of pregnancy, and rats fed an isocaloric normal-protein diet (17% protein) were used as controls. RESULTS: The low-protein diet reduced the levels of connexin 36 and ß-catenin protein in pancreatic islets. In rats fed the control diet, pregnancy increased the levels of phospho-[Ser(279/282)]-connexin 43, and it decreased the levels of connexin 36, ß-catenin and beta-actin mRNA as well as the levels of connexin 36 and ß-catenin protein in islets. The low-protein diet during pregnancy did not alter these mRNA and protein levels, but avoided the increase of levels of phospho-[Ser(279/282)]-connexin 43 in islets. Insulin secretion in response to 8.3 mmol/L glucose was higher in pregnant rats than in non-pregnant rats, independently of the nutritional status. CONCLUSION: Short-term protein restriction during pregnancy prevented the Cx43 phosphorylation, but this event did not interfer in the insulin secretion.
Asunto(s)
Comunicación Celular/fisiología , Diabetes Gestacional/dietoterapia , Dieta con Restricción de Proteínas , Uniones Intercelulares/metabolismo , Islotes Pancreáticos/metabolismo , ARN Mensajero/metabolismo , Actinas/metabolismo , Uniones Adherentes/metabolismo , Análisis de Varianza , Animales , Glucemia/análisis , Conexina 43/metabolismo , Conexinas/metabolismo , Diabetes Gestacional/prevención & control , Femenino , Uniones Comunicantes/metabolismo , Glucosa/administración & dosificación , Insulina/metabolismo , Secreción de Insulina , Embarazo , Ratas Wistar , Reacción en Cadena en Tiempo Real de la Polimerasa , beta Catenina/metabolismo , Proteína delta-6 de Union ComunicanteRESUMEN
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