Norethindrone alters apolipoprotein E concentration and isoform expression in rat plasma high-density lipoproteins

The administration of norethindrone, a synthetic progestin, to female rats caused marked decreases in the cholesterol and protein contents of high-density lipoproteins (HDL). A 84% decrease in the total apolipoprotein (apo) E of HDL was associated with a 80% decrease in the proportions of apoE isoforms E1 and E2, whereas E3 and E4 were unchanged. This appears to be the first demonstration of hormonally-induced modification of the apoE phenotype.