Absence of lipemia clearing factor lipase in human adipose tissue.

Lipoprotein lipase, or lipemia clearing factor lipase (which is more accurate terminology [l]) , is a heparin-activated enzyme which has been found in rat, beef, and pig heart (2). The adipose tissues of rats, rabbits, and especially chickens contain greater quantities of the enzyme (3). This latter observation led to the suggestion that the major site of lipoprotein lipase activity was in the adipose tissue, where it might function in chylomicron dissolution, and also in the lipolysis of depot fat with resultant free fatty acid release. Clearing factor lipase has also been demonstrated in rat plasma after fat feeding (4), and in the plasma of some humans (5, 6) without the prior injection of heparin, indicating a possible intravascular lipolytic role. The evidence supporting this point of view has recently been summarized (7). In view of these facts, the presence of clearing factor lipase activity in human adipose tissue was investigated.