Numerous studies have reported that women have a lipoprotein profile suggestive of a reduced risk of coronary heart disease (CHD). We have therefore tested whether the "protective" lipoprotein profile of women could be explained by differences in hepatic lipase (HL) or lipoprotein lipase (LPL) activities. In the present study, 14 non-obese healthy premenopausal women had higher plasma concentrations of high-density lipoprotein cholesterol (HDL-C), HDL2-C, HDL3-C, and HDL-apolipoprotein (apo) AI, and a higher ratio of HDL-C to low-density lipoprotein cholesterol (LDL-C) than 17 non-obese healthy men. Women also had lower plasma triglyceride (TG), HDL-TG, and apo B levels than men. Plasma postheparin LPL (PH-LPL) and HL activities showed no significant sex dimorphism, whereas abdominal and femoral adipose tissue (AT)-LPL activities were significantly higher in women (P < .005). In men, PH-LPL activity correlated significantly with plasma HDL2-C (r = .52, P < .05), LDL-C (r = -.47, P < .05), and apo B (r = -.56, P < .01) levels, as well as with the HDL-C/LDL-C ratio (r = .67, P < .005). No such relationships were found in women, with the exception of HL activity, which was negatively correlated with HDL-apo AI levels. In both genders, abdominal AT-LPL activity showed no significant association with plasma lipoprotein levels.(ABSTRACT TRUNCATED AT 250 WORDS)