Title: Vitamin E supplementation and caloric restriction promotes regulation of insulin secretion and glycemic homeostasis by different mechanisms in rats
Author: Zangerolamo, Lucas; Soares, G. M.; Rosa, L. R. O.; Santos, K. R.; Bronczek, G. A.; Marconato, E.; Carneiro, Everardo Magalhães; Barbosa Sampaio, Helena Cristina
Is part of: ADVANCES IN PHYSIOLOGY EDUCATION, v. 44, p. 124 - 130
Citation: Zangerolamo, Lucas; Soares, G. M.; Rosa, L. R. O.; Santos, K. R.; Bronczek, G. A.; Marconato, E.; Carneiro, Everardo Magalhães; Barbosa Sampaio, Helena Cristina; Vitamin E supplementation and caloric restriction promotes regulation of insulin secretion and glycemic homeostasis by different mechanisms in rats. ADVANCES IN PHYSIOLOGY EDUCATION, v.44, p. 124-130, 2020
Abstract: Vitamin E and caloric restriction have antioxidant effects in mammals. The aim of this study was to evaluate effects of vitamin E supplementation and caloric restriction upon insulin secretion and glucose homeostasis in rats. Male Wistar rats were distributed among the following groups: C, control group fed ad libitum; R, food quantity reduction of 40%; CV, control group supplemented with vitamin E [30 mg.kg(-1).day(-1)]; and RV, food-restricted group supplemented with vitamin E. The experiments ran for 21 days. Glucose tolerance and insulin sensitivity was higher in the CV, R, and RV groups. Insulin secretion stimulated with different glucose concentrations was lower in the R and RV groups, compared with C and CV. In the presence of glucose and secretagogues, insulin secretion was higher in the CV group and was lower in the R and RV groups. An increase in insulin receptor occurred in the fat pad and muscle tissue of groups CV, R, and RV. Levels of hepatic insulin receptor and phospho-Akt protein were higher in groups R and RV, compared with C and CV, while muscle phospho-Akt was increased in the CV group. There was a reduction in hepatic RNA levels of the hepatocyte growth factor gene and insulin degrading enzyme in the R group, and increased levels of insulin degrading enzyme in the CV and RV groups. Thus, vitamin E supplementation and caloric restriction modulate insulin secretion by different mechanisms to maintain glucose homeostasis.
Keywords: active learning; blended learning; educational intervention; physiology education; teaching methods; undergraduate courses;
Funding: The authors thank Adilson Ismael Alves dos Santos and Hercules Jonas Rebelato for their excellent technical assistance. This work was partially supported by grants from the Brazilian funding agencies Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP, grant 2012/01146-6), Apoio a Pesquisa Institucional Uniararas (PROPesq-Uniararas).