Post-heparin lipolytic activity and tissue lipoprotein lipase activity in the alloxan-diabetic rat.

It is widely assumed that measurement of lipolytic activity in post-heparin plasma (PHLA) reflects the activity of the enzyme lipoprotein lipase in extrahepatic tissues, i.e. adipose tissue, muscle and the heart. Apart from the findings of low PHLA in patients with Fredrickson’s type I (fat-induced) hyperlipoproteinaemia (Fredrickson, Ono & Davis, 1963), in which a defect in tissue lipoprotein lipase activity (LLA) is thought to occur, there is little evidence that PHLA reflects tissue LLA. This study was made to find out whether, in the rat, adaptive changes in PHLA and tissue LLA occur together. As there is evidence that adipose tissue is under hormonal control by insulin (Salaman & Robinson, 1966), we used the alloxan-diabetic rat as a model in which insulin deficiency occurs.