Endocrine System Diseases; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Nutritional and Metabolic Diseases
Clinical studies of the biochemical and molecular mechanisms of insulin action. My research interests include the study of normal physiologic regulation of metabolism during the fed and fasted state as well as during exercise as well as the metabolic disturbances, which occur with insulin resistance and diabetes. The studies include induction and reversal of insulin resistance in patients with Type 1 and 2 Diabetes, Prediabetic States, Obesity, Low Birth Weight and Aging. The studies involve the insulin clamp procedure in the 4T NMR instrument, in combination with stable istotope techniques and muscle biopsies to assess insulin action in liver, fat tissue and muscle.
In order to elucidate the physiologic regulations of insulin action as well as the defects in pathologic states, we use 13C and 31P NMR spectroscopic techniques using the 4T magnet to determine rate-limiting steps of insulin stimulated glucose metabolism in liver and muscle.* Lipid content of muscle and liver are assessed using 1H NMR spectroscopy also on the 4T instrument.* 13C NMR spectroscopy in combination with a 31P saturation transfer technique to assess rates of TCA cycle flux, ATP synthesis and energy coupling in muscle. * Natural abundance 13C NMR spectroscopy using the 4T instrument to measure liver glycogen concentrations in humans in combination with stable isotope techniques to determine rates of net hepatic glycogenolysis, and the relative contribution to whole body glucose production during short and long-term fasting, in patients with type 2 diabetes, Maturity Onset Diabetes of the Young (MODY), liver cirrhosis. * We are using 13C and 1H NMR spectroscopy at 4T to study the regulation of brain Metabolism (PC and TCA Flux and anaplerosis) in the elderly and in patients with type 1 diabetes, GDH defects and liver cirrhosis.