Effect of some steroid contraceptives on serum lipids of lactating goats.

To investigate the effect of synthetic contraceptive steroids on lipid metabolism plasma total lipids lipoprotein fractions plasma total triglycerides plasma cholesterol and plasma phospholipids were measured in blood samples taken from 12 postnatal goats who were divided into 6 groups: Group 1 received no medication; Group 2 received Deladroxate (150 mg hydroxyprogesterone acetophenide and 10 mg estradiol enanthate); Group 3 received Lyndiol 2.5 (2.5 mg lynestrenol and .075 mg mestranol); Group 4 received Lyndiol 1 (1 mg lynestrenol and .10 mg mestranol); Group 5 received .5 mg lynestrenol alone; and Group 6 received mestranol alone. All steroids were administerd in doses comparable to human prescriptions. Analysis of the blood samples taken every 2 weeks for 12 weeks after delivery showed that plasma total lipids remained unchanged in the control group during the experimental period but decreased from 14-19% in the other groups except for an increase of 6.6% in Group 4. Plasma triglycerides decreased in all groups ranging from an 8.5% drop in Group 1 to a 68.6% drop in Group 3. Group 4 initially showed a 71% jump in triglyceride levels before dropping to 23.2% below pretreatment levels. Plasma phospholipids and total cholesterol remained unchanged in the control group but dropped between 20 and 30% in the other groups. The cholesterol ester ratio remained unchanged in all groups. Marked changes in the beta/alpha lipoprotein ratio were found including increases of 32% in Group 1 and increases ranging from 17 to 82% in the other groups except for a 30% decline in Group 2. These documented changes in serum lipid concentrations during oral contraceptive administration should provide the basis for further intensive reasearch.