Alterations in the level of insulin receptor and GLUT-4 mRNA in skeletal muscle from rats fed a kidney bean ( Phaseolus vulgaris) diet

Abstract

1. 1. A decline in the level of circulating insulin was observed in rats fed a diet containing kidney bean 2. 2. Consumption of a diet containing kidney bean caused an increase in the level of mRNAs for the insulin receptor (327%) and GLUT-4 (185%) in the gastrocnemius muscle. In contrast there was only a small increase in the amount of actin mRNA (125%). Since the kidney bean-fed rats are euglycaemic the results suggest that insulin receptor and GLUT-4 mRNA levels are regulated in response to circulating insulin concentrations rather than glucose 3. 3. No increases in the level of insulin receptor and actin mRNA were evident in the soleus muscle of rats fed the diet containing kidney bean; however a decline was observed in the level of GLUT-4 mRNA 4. 4. It is proposed that a component of kidney beans, most likely the lectin phytohaemaglutinin, has systemic effects which lead to changes in expression of the insulin receptor and GLUT-4 genes and to the sensitivity of muscle to insulin.