Effects of Contraceptive Steroids on Carbohydrate Metabolism

Abstract

To further define the association of impaired glucose tolerance tests (GTT) and the administration of contraceptive steroids, 23 healthy nonobese women were selected for this study. Twelve subjects received cyclic ethinyl estradiol (100 μg) for the first 16 days, followed by dimethisterone (25 mg) plus ethinyl estradiol for 5 days. Eleven subjects received cyclic ethinyl estradiol 3-methyl ether (100 μg) plus ethynodiol diacetate (1 mg) for 20 days. Both oral and iv GTT were performed before and during the third cycle of treatment. The effects on carbohydrate metabolism were evaluated by means of statistical analysis of absolute and per cent changes in the paired samples of blood glucose, serum insulin and serum growth hormone (HGH) levels during the 2-hr tests. In addition, the area under the curves (area unit) was measured and used as an index for comparing relative quantitative changes. Our data indicate that both oral and iv GTT remain unchanged, but it was associated with a state of relative hyperinsulinism and a 3-fold increase in fasting ambulatory HGH levels. Although elevated HGH levels were readily suppressible by both oral and iv glucose, the estimated total HGH secretion during the 2-hr tests was significantly increased. Since HGH exerts a peripheral antiinsulin effect, increased insulin secretion as a compensatory mechanism probably explains the normal GTT's in these subjects. The insulinogenic response to oral GTT was much greater than iv GTT both before and after treatment.