Maternal diabetes increases small conductance Ca2+-activated K+ (SK) currents that alter action potential properties and excitability of cardiac motoneurons in the nucleus ambiguus.

Parasympathetic cardiac motoneurons (PCMNs) in the nucleus ambiguus (NA) play a key role in regulating cardiac functions. In this study, we examined the effects of maternal diabetes on excitability, action potential (AP) properties, and small conductance Ca(2+)-activated K(+) (SK) currents of PCMNs. Neonatal mice from diabetic (OVE26 female, NMDM) and normal (FVB female, control) mothers that had been mated with nondiabetic fathers (FVB male) were used.

Chronic high glucose lowers pyruvate dehydrogenase activity in islets through enhanced production of long chain acyl-CoA: prevention of impaired glucose oxidation by enhanced pyruvate recycling through the malate-pyruvate shuttle.

In islet beta-cells, the high expression of pyruvate carboxylase and the functional importance of the downstream anaplerosis pathways result in a unique characteristic whereby high glucose and fatty acids both increase production of a key fatty acid metabolite, long chain acyl-CoA, for signaling and enzyme regulation in beta-cells. We showed previously in islets that pyruvate dehydrogenase (PDH) activity is lowered by excess fatty acids (the so-called Randle effect). We have now investigated PDH activity and pyruvate metabolism in islets after 48-h culture at 16.

beta-Cell adaptation to insulin resistance. Increased pyruvate carboxylase and malate-pyruvate shuttle activity in islets of nondiabetic Zucker fatty rats.

The beta-cell biochemical mechanisms that account for the compensatory hyperfunction with insulin resistance (so-called beta-cell adaptation) are unknown. We investigated glucose metabolism in isolated islets from 10-12-week-old Zucker fatty (ZF) and Zucker lean (ZL) rats (results expressed per mg/islet of protein). ZF rats were obese, hyperlipidemic, and normoglycemic.