Contraceptive Steroid Effects on Lipids and Lipoproteins in Cynomolgus Monkeys

Seventy-three adult female cynomolgus monkeys fed an atherogenic diet were studied to determine the effect of two different combination contraceptive steroid preparations containing equivalent amounts of estrogen but different progestln components on plasma NpkJs and lipoproteins. Our hypothesis was that any high density llpoproteln (HDL) lowering effect of the contraceptive steroid preparations was proportional to the rise In total serum cholesterol caused by the progestins. For 2 years, one group (Ovral [Wyeth Laboratories], n=23) received 75 HQ norgestrel and 7.5 ng ethinyl estradiol dally, while another (Demulen [Searle & Co.], n=25) received 150 /tg ethynodlol dlacetato and 7.5 /ig ethinyl estradiol dally. The control group (n=24) received no treatment On average, the two oral contraceptive groups had higher total serum cholesterol and triglycerlde concentrations but lower HDL cho-lesterol concentrations and smaller low density lipoproteins (LDL) compared with the control group. There was an Inverse relationship between total serum cholesterol and HDL cholesterol for all three groups, but at any given total serum cholesterol concentration between 350 and 500 mg/dl, the Ovral group had HDL cholestero