Cynomolgus monkeys (Macaca fascicularis) fed monkey chow (n = 10) had a mean +/- SD post-heparin plasma lipoprotein lipase (LPL) activity level (14.7 +/- 5.5 units/ml) similar to that found in human beings (15.7 +/- 3.9 units/ml). However, the hepatic triglyceride lipase (H-TGL) in these monkeys was extremely low (0.5 +/- 0.3 units/ml) when compared with that in human beings (10.9 +/- 4.3 units/ml). The consumption of isocaloric atherogenic diets (0.2 mg cholesterol/Cal) with either saturated (P/S = 0.34) or polyunsaturated (P/S = 2.2) fat led to increased LPL activity levels (27.6 +/- 6.5 and 28.8 +/- 16.1 units/ml, respectively) and the accumulation of plasma low density lipoprotein cholesterol (LDL-C). The results indicate that cholesterol-containing atherogenic diets with either primarily saturated or polyunsaturated fat have similar potential for the increase of LPL activity. However, it is not clear whether the high dietary cholesterol content represents an obligatory component for the increase of LPL. We speculate that the high level of LPL in cynomolgus monkeys when fed a cholesterol-rich, high fat diet could be a contributing factor to the accumulation of excessive plasma LDL-C.
