Metabolic profiles of endogenous and ethynyl steroids in plasma and urine from women during administration of oral contraceptives.

Conjugated ethynyl and endogenous steroids in plasma and urine from two women taking an oral contraceptive (Conlumin) containing 1 mg norethindrone and 50 micrograms mestranol have been analyzed by methods based on anion and ligand exchange chromatography and gas chromatography-mass spectrometry. Conjugated norethindrone and its reduced metabolites with 3 alpha,5 alpha, 3 alpha,5 beta, 3 beta,5 beta and 3 beta,5 alpha configurations were identified in the fluids. The quantitatively major metabolites in plasma were a disulphate of the 3 alpha,5 alpha isomer and a monosulphate of the 3 alpha,5 beta isomer. The renal clearance of the former compound was low. The major urinary metabolite of norethindrone was the 3 alpha,5 beta isomer conjugated with glucuronic or sulphuric acid. Disulphates constituted only a small portion of urinary ethynyl steroids. Metabolic profiles of endogenous neutral steroids in plasma and urine during the contraceptive cycle were compared with profiles during a physiological menstrual cycle. The concentrations of steroids in plasma during contraception were similar to those during the follicular and mid phases of the menstrual cycle, whereas levels of progesterone metabolites were higher in the luteal phase. The urinary excretion of steroids was 15-30% lower during the contraceptive cycle, due to a decrease in excretion of C21O5 steroids, 11-oxygenated androgens and etiocholanolone. The increase of urinary progesterone metabolites seen during the luteal phase was not observed during contraception, but the excretion of 5 beta-pregnane-3 alpha,20 alpha-diol glucuronide was higher than during the follicular and mid phases of the menstrual cycle.

Chromatographic patterns of urinary ethynyl estrogen metabolites in various populations.

Radioactive mestranol (ME) and/or ethynylestradiol (EE) were administered to women in Nigeria, Sri Lanka, and the USA, and the types and patterns of radioactive urinary conjugates examined by Sephadex LH-20 chromatography. There are no differences in the total excretion of urinary radioactivity over 3 days. Consistent geographic differences appear to be present in the proportion of 3-, 17-, and 3,17-glucuronides. If confirmed on larger population samples, these observations may indicate significant geographic differences in the hepatic metabolism of ethynyl estrogens. High performance liquid chromatographic patterns of the urinary aglycone metabolites of ME and EE were examined in a number of women. The separation was accomplished on a Chromegaprep Diol column with a gradient of isopropanol in heptane. Ethynyl estrogen metabolism shows considerable individual variation. EE is usually the principal compound escreted following ME or EE administration. Unmetabolized ME is present in the ME profiles. The profiles of EE and ME are similar, with EE demonstrating a more complex pattern. Oxidative metabolism occurs chiefly at positions 2, 6 and 16 and is fairly extensive in the USA subjects. The Sri Lankan women generally show less of the oxidative products and the Nigerian group display a notable lack of oxidative metabolism. There is no difference in the metabolic patterns of long-term oral contraceptive users vs. non-users. Using silver sulfoethylcellulose column chromatography, from 14.1 to 34.7% of the excreted radiolabeled aglycones are non-ethynyl (i.e., either D-homo or de-ethynylated estrogens).

PIP: Types and patterns of radioactive urinary conjugates were examined by Sephadex LH-20 chromatography after ingestion of radiolabeled mestranol and/or ethinyl estradiol in a variety of populations. Women in Nigeria, Sri Lanka, and the United States were given the radioactive estrogens. Over 3 days, no differences in total excretion of urinary radioactivity were found. However, there were consistent geographical differences in the proportion of 3-, 17-, and 3,17-glucuronides, indicating significant geographical differences in hepatic metabolism of ethinyl estrogens. Then high-performance liquid chromatographic patterns of urinary aglycone metabolites of mestranol and ethinyl estradiol were studied after successful separation on a Chromegaprep Diol column. Ethinyl estrogen metabolism showed great individual variation. Ethinyl estradiol was the principal compound excreted after ingesting either ethinyl estradiol or mestranol. Unmetabolized mestranol was found as well. Ethinyl estradiol and mestranol profiles were similar, with ethinyl estradiol demonstrating a more complex pattern. U. S. subjects displayed extensive oxidative metabolism (Positions 2, 6, and 16), Sri Lankans less Nigerians very little if any. No difference in metabolic patterns was seen among long-term vs. short-term users vs. nonusers.

Influence of rifampicin treatment on the metabolic fate of [4-14C] mestranol in women.

[4-14C] Mestranol was administered to 2 rifampicin treated and to 3 untreated hysterectomised women with normal liver functions. The urinary excretions of mestranol, ethynylestradiol, 2-hydroxy-ethynylestradiol and of the total radioactivity were measured within the following 5 days. After this period the total urinary excretion of radioactivity amounted to approx. 43% (38%-50%) of the administered dose and no difference was found for the rifampicin treated and untreated women. Moreover, in the urines of both of these groups the same amounts of radioactive mestranol (1.1%-6.3% of the urinary radioactivity) and 2-hydroxy-ethynylestradiol (0.9%-3.9% of the urinary radioactivity) were measured. In contrast, the urinary excretion of ethynyl-estradiol was definitely lower in the rifampicin treated women (3.5% and 4.9% of the urinary radioactivity) as compared to the control group (15%-23%).