Metabolism of apolipoproteins A‐I and A‐ll and its influence on the high density lipoprotein subfraction distribution in males and females

Rate zonal ultracentrifugation of plasma samples from ten healthy age-matched volunteers (five males, five females) indicated that the high density lipoprotein subfraction ratio (HDL ₂:HDL ₃) in females was significantly higher than in males. The cause of this phenomenon was investigated by simultaneous examination of the metabolism of the major HDL apoproteins (apoA-I and apoA-II) in both groups. The results show that there is no significant sex-related difference in the plasma pool size, fractional catabolic rate, or synthetic rate of either apoprotein. We conclude that the increased HDL ₂:HDL ₃ ratio in females versus males does not derive from measurable differences in the metabolic handling of either apoprotein.