Changes in apolipoprotein B100-containing lipoprotein metabolism due to an estrogen plus progestin oral contraceptive: A stable isotope kinetic study

Abstract

Context: Oral contraceptives with estrogen plus progestin are likely to influence apolipoprotein B (apoB)-containing lipoprotein metabolism by changing the expression of different enzymes or receptors that play a major role in this metabolism. However, the precise changes in apoB kinetic parameters induced by oral contraceptives that are now currently used are unknown. Objectives: We studied the impact of Moneva, containing 30 μg ethinylestradiol and 75 μg gestodene, on the apoB production rate and fractional catabolic rate of very-low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), and low-density lipoprotein (LDL). Design: Using a 16-h [13C]leucine infusion, we performed an apoB kinetic study in nine normolipidemic women before and 3 months after beginning Moneva. Results: On Moneva, serum triglycerides increased moderately (+12%, P = 0.04) in the fed state, whereas serum LDL remained unchanged. LDL particles were richer in triglycerides in women on Moneva (7.5 ± 1.5 vs. 4.3 ± 1.0% of total LDL mass, P < 0.01). The apoB production rate of VLDL, IDL, and LDL increased by 49 (P=0.04), 55 (P=0.05), and51%(P=0.01), respectively. The fractional catabolic rate of apoB in LDL increased by 36% (P=0.04). Consequently, the serum LDL apoB pool size remained unchanged (26.49 ± 6.98 vs. 23.96 ± 5.37 mg/kg). Conclusion: Oral contraception with ethinylestradiol plus gestodene induces an increase in the production rate of apoB-containing lipoproteins all along the VLDL→IDL→LDL cascade. The increased production rate of apoB in LDL is counterbalanced by a higher fractional catabolic rate of apoB in LDL, thus precluding an increase in the concentration of atherogenic LDL particles. Copyright © 2010 by The Endocrine Society.