Changes in Insulin Secretion, KATP and Ba Currents in Rat Pancreatic Beta Cells from Rats with Metabolic Syndrome, Induced by a High Sucrose Diet

Abstract

Metabolic syndrome (MS) increases the probability toh develop type 2 diabetes mellitus. We studied the effect of a high-sucrose diet on pancreatic beta cells physiology. Wistar adult male rats were fed with a 20 % sucrose solution in drinking water or control, which received plain water, for 24 weeks. After treatment, compared to controls, treated rats group increased body weight by 22%, due to peripancreatic and epididimal adipose tissue that increased by 135 and 154 %, respectively. Tey were also hyperglycemic, hyperinsulinemic and hypertriglyceridemic, without changes in plasmatic cholesterol. We concluded that this group developed metabolic syndrome (MS).We recorded the activity of ATP-sensitive potassium channels (KATP) in beta cells. Channel conductance was 50 ± 0.1 and 51 ± 7 pS for control and MS, respectively; however, the Kd for ATP was 10.1 ± 0.9 μM for MS cells, while the control was 19.3 ± 0.001 μM, indicating that KATP channels in MS rats were more sensitive to ATP. Beta cells from MS showed three behavior modes in whole cell-barium current (IBa). The peak current density in 50 % of the cells decreased by 40 %, while in 35 % of the cells, IBa increased by 90 %, compared to controls. In 15 % of the cells no IBa was recorded. These results indicate that a high sucrose diet induced MS and modified beta cell functions, leading to ATP hypersensitivity and altered IBa, and insulin secretion. Supported by Instituto de Ciencia y Tecnologia del Distrito Federal PICDS08-72.