Influence of total parenteral nutrition on tissue lipoprotein lipase activity during chronic and acute illness

This study examines the influence of total parenteral nutrition (TPN) compared with 5% dextrose (D5) infusion on skeletal muscle and adipose tissue lipoprotein lipase (LPL) activity in nutritionally depleted, injured and infected patients. The plasma concentrations of glucose, free fatty acid (FFA), triglyceride and insulin were also measured. During TPN, nutritionally depleted subjects showed an increase in adipose tissue LPL activity, "fat cell size," and plasma insulin concentration. Skeletal muscle LPL activity and plasma FFA concentration decreased. In comparison, trauma patients showed a less marked rise in adipose tissue LPL activity and skeletal muscle LPL activity increased. Infected patients had a much smaller rise in adipose tissue LPL activity than either of the other groups, and muscle activity rose. The depleted and injured patients showed a linear relationship between adipose tissue LPL activity and plasma insulin concentration and an inverse hyperbolic relationship between adipose tissue LPL activity and plasma FFA concentration.