Lipoprotein lipase secretion from isolated rat fat cells of different size

Lipoprotein lipase(LPL) release from isolated small fat cells from young rats and large fat cells from older, fatter rats was compared during in vitro incubation at 30 degrees C. Although large fat cells had nearly three times higher cellular LPL activity, they secreted similar amounts of LPL activity into the incubation medium under both basal conditions (Krebs Ringer bicarbonate buffer containing 4% albumin and 6mM glucose) and after stimulation of LPL release by 5% human serum, or serum plus 1 U/ml heparin. These data suggest that previous observations of an altered tissue distribution of LPL in adipose tissue containing large fat cells can be at least in part explained by an alteration at the level of LPL secretion.