REGIONAL DIFFERENCES AND EFFECT OF WEIGHT-REDUCTION ON HUMAN FAT-CELL METABOLISM

Abstract. The metabolism of adipocytes from severely obese patients was investigated before and after weight was reduced by jejuno‐ileal by‐pass. After weight reduction lipolysis and glucose incorporation into triglycerides were decreased as was the cell size. The effect of submaximal concentrations of insulin on glucose incorporation increased with weight reduction implying increased cellular insulin sensitivity. The rate of glucose incorporation and basal lipolysis in the adipocytes correlated directly with the fasting plasma insulin level before weight reduction. After weight reduction there was a positive correlation between the decrease in glucose metabolism and the reduction in the plasma insulin level. These data support the concept that plasma insulin may be important for the long‐term regulation of glucose metabolism and lipolysis in fat cells. In other patients with normal body weight, studies on regional differences in adipocyte metabolism showed that fat cells from the subcutaneous abdominal region responded better to both noradrenaline and insulin than femoral fat cells. The differences between these sites were less pronounced during incubation with isopropylnoradrenaline, suggesting there was increased α‐receptor activity in the femoral region. Adipocytes in the abdominal subcutaneous region are thus metabolically much more active than those in the femoral region. This might explain why several blood parameters such as arterial free fatty acid and glycerol levels correlate with lipolysis of abdominal but not femoral cells and why plasma insulin and triglyceride levels correlate with abdominal but not femoral fat cell size. Also, the responsiveness of adipocytes in the abdominal region may explain why cells in this region decreased more in size than those in the femoral region during weight reduction. Copyright © 1979, Wiley Blackwell. All rights reserved