2 Clinical Trials for Various Conditions
Obesity is associated with reduced growth hormone (GH) secretion. GH secretion is regulated by nutritional stimuli including fasting, insulin, glucose and free fatty acids. However, the role of micronutrients, such as vitamins, on GH secretion has not been investigated in much detail. Vitamin C levels are also reduced in obesity, and the investigators recently demonstrated a possible role for dietary vitamin C intake in the regulation of GH secretion in two preliminary retrospective studies. The investigators therefore propose a more detailed prospective physiological study to examine the effects of increasing dietary vitamin C intake on GH secretion in a physiologic, intervention study. The investigators hypothesize that increasing vitamin C concentrations in obese subjects with sub-optimal plasma vitamin C levels and reduced GH secretion will increase GH secretion.
Obesity is associated with reduced growth hormone (GH) secretion. Reduced GH secretion in obesity is associated with increased cardiovascular disease risk. However, it is not yet known how reduced GH increases cardiovascular disease risk in obesity. The investigators hypothesize that reduced GH contributes to dysfunction of the mitochondria. Therefore, the investigators hypothesize that treatment of obese subjects with reduced GH secretion with GH will improve mitochondrial function and that this improvement in mitochondrial function will contribute, in part, to the effects of GH to improve metabolic parameters in obesity. The investigators propose to study skeletal muscle mitochondria in obese subjects with reduced GH secretion using magnetic resonance spectroscopy and muscle biopsies before and after treatment with GH.