PKC delta (Phospho-Tyr64) ELISA Kit

C57BL/6J and 129S6/Sv (B6 and 129) mice differ dramatically in their susceptibility to developing diabetes in response to diet- or genetically induced insulin resistance. A major locus contributing to this difference has been mapped to a region on mouse chromosome 14 that contains the gene encoding PKC delta. Here, we found that PKC delta expression in liver was 2-fold higher in B6 versus 129 mice from birth and was further increased in B6 but not 129 mice in response to a high-fat diet. PRKCD gene expression was also elevated in obese humans and was positively correlated with fasting glucose and circulating triglycerides. Mice with global or liver-specific inactivation of the Prkcd gene displayed increased hepatic insulin signaling and reduced expression of gluconeogenic and lipogenic enzymes. This resulted in increased insulin-induced suppression of hepatic gluconeogenesis, improved glucose tolerance, and reduced hepatosteatosis with aging. Conversely, mice with liver-specific overexpression of PKC delta developed hepatic insulin resistance characterized by decreased insulin signaling, enhanced lipogenic gene expression, and hepatosteatosis. Therefore, changes in the expression and regulation of PKC delta between strains of mice and in obese humans play an important role in the genetic risk of hepatic insulin resistance, glucose intolerance, and hepatosteatosis; and thus PKC delta may be a potential target in the treatment of metabolic syndrome.

This study aimed to determine whether protein kinase C (PKC) delta plays a role in the glucose intolerance caused by a high-fat diet, and whether it could compensate for loss of PKC epsilon in the generation of insulin resistance in skeletal muscle. Prkcd (-/-), Prkce (-/-) and wild-type mice were fed high-fat diets and subjected to glucose tolerance tests. Blood glucose levels and insulin responses were determined during the tests. Insulin signalling in liver and muscle was assessed after acute in vivo insulin stimulation by immunoblotting with phospho-specific antibodies. Activation of PKC isoforms in muscle from Prkce (-/-) mice was assessed by determining intracellular distribution. Tissues and plasma were assayed for triacylglycerol accumulation, and hepatic production of lipogenic enzymes was determined by immunoblotting. Both Prkcd (-/-) and Prkce (-/-) mice were protected against high-fat-diet-induced glucose intolerance. In Prkce (-/-) mice this was mediated through enhanced insulin availability, while in Prkcd (-/-) mice the reversal occurred in the absence of elevated insulin. Neither the high-fat diet nor Prkcd deletion affected maximal insulin signalling. The activation of PKC delta in muscle from fat-fed mice was enhanced by Prkce deletion. PKC delta-deficient mice exhibited reduced liver triacylglycerol accumulation and diminished production of lipogenic enzymes. Deletion of genes encoding isoforms of PKC can improve glucose intolerance, either by enhancing insulin availability in the case of Prkce, or by reducing lipid accumulation in the case of Prkcd. The absence of PKC epsilon in muscle may be compensated by increased activation of PKC delta in fat-fed mice, suggesting that an additional role for PKC epsilon in this tissue is masked.