Context: The impact of estrogen plus progestin as an oral contraceptive on high density lipoprotein (HDL) apolipoprotein (apo) AI metabolism in humans is poorly understood.
Objectives: This study was designed to measure the in vivo effect of Moneva (30 microg ethinylestradiol, 75 microg gestodene) on HDL apoAI production rate and fractional catabolic rate.
Design: Using (13)C-leucine, we performed two kinetic studies in the fed state in 10 normolipidemic young women, before and 3 months after beginning Moneva.
Results: On Moneva, serum triglycerides increased by 12% (P = 0.03) in the fed state, whereas low-density lipoprotein and HDL cholesterol remained unchanged. HDL apoAI pool size and production rate were increased by 9.2% (67.3 +/- 7.1 vs. 61.6 +/- 6.7 mg x kg(-1); P = 0.05) and 26.5% (14.3 +/- 2.7 vs. 11.3 +/- 2.2 mg x kg(-1) x d(-1); P = 0.02), respectively. HDL apoAI fractional catabolic rate was not significantly modified. Three-month treatment by Moneva induced a shift of HDL size distribution from HDL2 toward HDL3 (HDL3 = 51.5 +/- 8.1 vs. 46.5 +/- 9.2% of total HDL; P = 0.02) and an increase in the proportion of apoAI among HDL components (38.8 +/- 4.3 vs. 34.4 +/- 2.8%; P = 0.01).
Conclusion: Oral contraception by estrogen plus progestin induces changes in HDL apoAI metabolism characterized by an increase in production rate and pool size, with a higher proportion of HDL3 particles. Whether or not these changes are beneficial to prevent atherosclerosis has to be explored further.