Increase of the lipoprotein‐lipase activity in human skeletal muscle during clof ibrate administration

Abstract

Lipoprotein-lipase activity was determined in tissue from the skeletal muscle of the leg and the subcutaneous adipose tissue of the abdomen in 14 patients before and after 1 mo. of clofibrate administration. The concentrations of serum triglycerides decreased by, on the average, 37% in a group of 13 patients which mainly consisted of subjects with type-IV hyperlipoproteinemia. Clofibrate administration was associated with an average increase of the skeletal muscle-tissue lipoprotein-lipase activity of 50% (P < 0.005). There was a significant correlation between the percentage changes in skeletal muscle-tissue lipoprotien-lipase activity and those of the triglycerides concentrations and the K2-values in an i.v. fat tolerance test during clofibrate treatment. Adipose-tissue lipoprotein-lipase activity did not change significnatly. One patient with type-I hyperlipoproteinemia had very low values of skeletal muscle-tissue lipoprotein-lipase activity and moderately low adipose-tissue lipoprotein-lipase activity. In this patient, neither the tissue lipoprotein-lipase activity nor the triglycerides concentration changed during clofibrate therapy. Fasting serum insulin concentrations decreased significantly during clofibrate administration and the percentage decrease was significantly during clofibrate administration and the percentage decrease was significantly correlated to the percentage increase of skeletal-muscle lipoprotein-lipase activity. The lowering of insulin levels is a possible mechanism through which glucagon activity is enhanced and this may increase skeletal muscle-tissue lipoprotein-lipase activity.