Heterogeneity of primary lipoprotein lipase deficiency

Abstract

Lipoprotein lipase activity appeared in plasma within 10 min of beginning a heparin infusion in control subjects in whom adipose tissue lipoprotein lipase activity was normal. Plasma lipoprotein lipase activity was maintained throughout a heparin infusion lasting 4–6 hr. Three subjects with primary diminished adipose tissue lipoprotein lipase activity had markedly decreased lipoprotein lipase activity for the duration of the heparin infusion. However, the findings in two additional subjects suggest that the activity released during the early phase and during the late phase of the heparin infusion might come from different tissues. One subject had no adipose tissue lipoprotein lipase activity, but had levels of lipoprotein lipase in postheparin plasma similar to controls during the early phase of the heparin infusion. The other subject had normal adipose tissue lipoprotein lipase activity in the fasted and fed state, yet had little lipoprotein lipase activity in postheparin plasma during the early phase of the heparin infusion. This patient developed levels similar to that seen in plasma in the control subjects at the end of the heparin infusion. These findings suggest that (1) the activity that appears soon after initiating the heparin infusion is released from tissues other than adipose tissue, while that appearing later is of adipose tissue origin and (2) subjects with primary abnormalities of lipoprotein lipase form a heterogenous group of individuals.