Expression Of Protein Kinase C Isoforms In Pancreatic Islets And Liver Of Male Goto-Kakizaki Rats, A Model Of Type 2 Diabetes

Protein kinase C (PKC) is a family of protein kinases controlling protein phosphorylation and playing important roles in the regulation of metabolism. We have investigated expression levels of PKC isoforms in pancreatic islets and liver of diabetic Goto-Kakizaki (GK) rats with and without insulin treatment to evaluate their association with glucose homeostasis. mRNA and protein expression levels of PKC isoforms were assessed in pancreatic islets and liver of Wistar rats and GK rats with or without insulin treatment. PKC alpha and PKC zeta mRNA expressions were down-regulated in islets of GK compared with Wistar rats. PKC alpha and phosphorylated PKC alpha (p-PKC alpha) protein expressions were decreased in islets of GK compared with insulin-treated GK and Wistar rats. PKC zeta protein expression in islets was reduced in GK and insulin-treated GK compared with Wistar rats, but p-PKC zeta was decreased only in GK rats. Islet PKC epsilon mRNA and protein expressions were lower in GK compared with insulin-treated GK and Wistar rats. In liver, PKC delta and PKC zeta mRNA expressions were decreased in both GK and insulin-treated GK compared with Wistar rats. Hepatic PKC zeta protein expression was diminished in both GK rats with and without insulin treatment compared with Wistar rats. Hepatic PKC epsilon mRNA expression was down-regulated in insulin-treated GK compared with GK and Wistar rats. PKC alpha, PKC epsilon, and p-PKC zeta expressions were secondary to hyperglycaemia in GK rat islets. Hepatic PKC delta and PKC zeta mRNA expressions were primarily linked to hyperglycaemia. Additionally, hepatic PKC epsilon mRNA expression could be under control of insulin.