Characterization of very-low-density lipoproteins isolated from baboons, and fractionated using heparin-Sepharose chromatography

Acute physical exercise alters apolipoprotein E and C-III concentrations of apo E-rich very low density lipoprotein fraction

To evaluate the influence of exercise on the apolipoprotein (apo) composition of very low density lipoprotein (VLDL) subfractions, we exercised 6 sedentary men for 30 min, 1 h after a fatty meal. VLDL fractions from samples drawn 4, 6 and 8 h post-prandially were separated from pre-stained plasma by high performance liquid chromatography and fractionated to apo E-poor (heparin-unbound) and apo E-rich (heparin-bound) fractions. The postprandial peak area (volts) and apo E, C-II and C-III concentrations (mg/dl) of post-exercise VLDL fractions were compared with corresponding postprandial values obtained at rest. Plasma triglycerides (TG) levels (mg/dl) were significantly lower 4 (P < 0.05), 6 (P < 0.02) and 8 h (p < 0.05) postprandially; the apo E-poor VLDL fraction was not modified by exercise and its apo concentrations were in the low range of detection; the apo E-rich VLDL peak area significantly decreased 4 (P < 0.01), 6 (P < 0.01) and 8 h (P < 0.05) postprandially; the apo E concentration of apo E-rich VLDL was significantly lower 4 (P < 0.02) and 6 h (P < 0.05) postprandially; the apo C-III concentration of apo E-rich VLDL significantly increased, 4 and 6 h postprandially (P < 0.05). Apo E-rich VLDL is, presumably, the metabolically active fraction of the particle and may regulate plasma TG level following exercise. The metabolic role of apo E-poor VLDL remains to be defined.