TURNOVER AND OXIDATION OF PLASMA GLUCOSE IN LEAN AND OBESE HUMANS

D-glucose-14C (UL) was infused intravenously at a constant rate for 6 1 2 hours into 9 lean and 13 obese subjects with indwelling arterial and venous catheters. The lean subjects were fasting from 7 hours to 7 days and the obese from 7 hours to 33 days. O2 uptake, CO2 output, and rates of glucose turnover and oxidation of plasma glucose were measured. The plasma glucose level ranged from 58 mg. 100 ml. to 99 mg. 100 ml. The rate of turnover of plasma glucose was calculated from the infusion rate of the labeled glucose and from the specific activity of plasma glucose. There were straight line correlations between plasma glucose level, glucose oxidation, and glucose turnover rate. The plasma FFA level ranged from 0.366 to 1.829 μEq./ml. There was an inverse relationship between plasma FFA level and glucose turnover. Positive correlation was found between glucose turnover and glucose oxidation and between RQ and per cent CO2 derived from plasma glucose. These correlation studies indicate that the interrelations between fat and glucose metabolism during short and prolonged starvation are similar in lean and obese individuals. © 1969.