Pathogenetic role of adipose tissue lipase deficit for development of hypertriglyceridaemia

In 87 patients (74 males, 13 females; age 43 +/- 9.2 years) covering a wide range of triglyceride (TG) concentrations (8.8 to 80.7 mmol/l) the turnover of total serum TG has been measured using the technique of labelling endogenously synthesized TG with 3H-glycerol. In parallel, lipoprotein lipase activity in adipose tissue and the adipose-tissue lipase activity in post-heparin plasma have been assessed following an oral 50 g glucose load. Despite the well-recognized function of this enzyme for intravascular lipolysis no direct relationship between lipase activities and fractional catabolic rates (FCR), reflecting TG removal processes, was found. On the other hand, relative enzyme activities (per TG moles) are positively correlated with the FCR. However, a detailed analysis of this relationship revealed that only in HTG patients whose FCR are below 0.210 h-1 a rate-limiting influence of a relative lipase deficit can be shown. In these patients, a statistically significant elevation of concentrations of free fatty acids is supposed to contribute to the impairment of the TG removal.