Subcutaneous Insulin Promotes Liver Glucose Metabolism
Benefit in type 1 diabetes modulated by reducing fasting gluconeogenesis and glycogen cycling
WEDNESDAY, June 8 (HealthDay News) -- Increased fasting gluconeogenesis (GNG) and glycogen cycling is seen in patients with poorly controlled type 1 diabetes (T1D), but continuous subcutaneous insulin infusion (CSII) improves these abnormalities, according to a study published in the June issue of Diabetes.
Michaela Kacerovsky, M.D., from the Karl-Landsteiner Institute for Endocrinology and Metabolism in Vienna, Austria, and colleagues investigated the effect of CSII on normalization of hepatic glycogen metabolism in a study population which included patients with T1D with poor glycemic control (T1Dp), CSII-treated T1D with improved glycemic control (T1Di), and controls without diabetes. They measured liver glycogen synthesis and glycogenolysis using 13C magnetic resonance spectroscopy. Endogenous glucose production (EGP), GNG, glycogen phosphorylase (GP) flux, and gluconeogenic flux were also measured.
The investigators found that net hepatic glycogen synthesis was similar in T1Di and controls, but was 70 percent lower in T1Dp than controls. T1Dp had significantly increased EGP compared to both T1Di and controls during fasting (25 and 42 percent higher, respectively). In addition, T1Dp had significantly increased GNG compared to both T1Di and controls (74 and 67 percent higher, respectively). GP flux was higher than net glycogenolysis in T1Dp but was similar in both T1Di and controls. Glycogen cycling accounted for 47 percent of the GP flux in T1Dp.
"This study shows that long-term improvement of glycemic control using CSII-pump improves abnormal hepatic glucose metabolism in T1D even despite short-term hyperglycemia," the authors write.