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PubMed1984

Studies on the role of intestinal bacteria in metabolism of synthetic and natural steroid hormones.

Administration of antimicrobial agents to subjects taking oral contraceptives has been reported to lead to contraceptive failure and subsequent pregnancy. In women taking oral contraceptives antimicrobial agents could have an effect on both endogenous hormone levels and on the metabolism of the exogenously administered steroids. To investigate these possibilities, antimicrobial agents were administered for short periods to normal women taking various steroid drugs: Megestrol acetate (MA), medroxyprogesterone acetate (MPA), norethisterone (NET), a combination of NET and ethinylestradiol (EE) or a combination of lynestrenol and EE. During ampicillin administration the 24-h morning plasma concentrations of MA, MPA and NET were increased compared to the control values. In the MA and MPA experiments the afternoon values were determined and also found to be increased. In the subjects taking oral contraceptives plasma EE concentration showed a tendency to decrease during ampicillin administration on the third, fourth or fifth morning of ampicillin administration, but was never lower than the pretreatment values. In other experiments plasma estrone (E1) and estradiol (E2), urinary total E1, E2 and estriol (E3) and fecal unconjugated and conjugated E1, E2 or E3 were determined by RIA before, during and after administration of oxytetracycline (2 X 500 mg/day for 5 days) to 5 young male subjects. Furthermore urinary and fecal estrogens were determined in 1 male subject after administration of erythromycin for 6 days and in 2 normally menstruating women after tetracycline and trimethoprim administration, respectively. During treatment with antimicrobial drugs an increase in the excretion of fecal conjugated and, with the exception of the oxytetracycline experiments, also of unconjugated estrogens paralleled a decrease in urinary estrogen excretion, especially for E2 and E3. In both urine and feces the E1/E2 and E1 + E2/E3 ratios increased due to diminished reductive metabolism of estrogens in the gut. No significant effects on plasma unconjugated estrogen concentrations were observed. The results suggest that the intestinal bacterial flora plays a significant role in estrogen metabolism. However, further studies are necessary, because our results do not explain why administration of antibiotics may cause contraceptive failure.

Adult↗
PubMed1987

The characterization of sulphated metabolites of norethindrone in human milk after oral administration of contraceptive steroids.

The excretion of ethynyl steroids in milk from a lactating woman taking a daily dose of an oral contraceptive (Conlumin) containing 1 mg of norethindrone and 50 micrograms of mestranol has been studied. Milk was diluted with aq. triethylamine sulphate and steroids were extracted on a Sep-Pak C18 cartridge at 60-64 degrees C. Groups of unconjugated steroids, glucuronides, mono- and disulphates were separated on triethylaminohydroxypropyl Sephadex LH-20. Following hydrolysis and further purification, steroids possessing an ethynyl-substituent were isolated by chromatography on sulphohydroxypropyl Sephadex LH-20 in silver form. Gas chromatographic-mass spectrometric analysis of the O-methyloxime-trimethylsilyl ether derivatives of these steroids, showed the presence of norethindrone and mestranol in the free fraction and of tetrahydro metabolites of norethindrone with 3 alpha,5 alpha, 3 alpha,5 beta and 3 beta,5 alpha configurations in the mono- and disulphate fractions. The disulphate of the 3 alpha,5 alpha isomer was the most abundant ethynyl steroid in milk after 13 days of administration. The site of conjugation of the monosulphates was established by acetylation prior to solvolysis and analysis by gas chromatography-mass spectrometry. This showed that the 3 alpha,5 alpha isomer was conjugated mainly in the 17 beta-position while the 3 alpha,5 beta isomer was conjugated at C-3.

Adult↗
PubMed1975

Radioimmunoassay of serum medroxyprogesterone acetate (Provera) in women following oral and intravaginal administration.

A radioimmunoassay (RIA) method for measuring medroxyprogesterone acetate (MPA, Provera) in serum has been developed utilizing benzene:iso-octane extraction, 3H-MPA to assess procedural losses, goat anti-MPA-3-(0-carboxymethyl) oxime-bovine serum albumin serum and dextran-coated charcoal separation. Control serum blanks were undetectable, 200 pg/ml of MPA was measurable with a high reliability, and intra- and interassay coefficients of variation were 6 and 13 percent, respectively. MPA added to control serum was quantitatively recovered. Serum MPA levels measured in 2 women after ingestion of 10 mg MPA rose to 3.4 to 4.4 ng/ml within 1 to 4 hours after oral intake and fell rapidly thereafter to 0.3 to 0.6 ng/ml within 24 hours. Insertion of Silastic intra-vaginal rings (IVRs), containing 100 or 200 mg of MPA, into 4 women for periods of 3 weeks resulted in a rapid rise of serum MPA after insertion, rather stable MPA levels of 0.9 to 1.6 ng/ml while the IVRs were in place, and a rapid decline of serum MPA following IVR removal. Serum estradiol-17beta and progesterone concentrations, measured about 3 times a week in these patients, indicated that ovulation was consistently inhibited. The serum MPA levels observed in this study were approximately 5 times lower than those reported by other investigators using a double-antibody RIA of MPA in unextracted serum.

Administration, Oral↗
PubMed1977

In vitro steroid metabolic studies in human testes I: Effects of estrogen on progesterone metabolism.

A technique of incubation of testicular tissue in vitro with radiolabeled precursors was applied in the investigation of the steroid biosynthesis by testes of four young men after long-term, high-dose estrogen treatment. A positive correlation between plasma and testicular steroid levels, and in vitro capacity of the testes to metabolize progesterone was demonstrated. Estrogen administration produced a very significant inhibition of plasma and testicular levels of testosterone. The in vitro synthesis of testosterone from progesterone was very severely impaired; especially 17alpha-hydroxylation of progesterone. 20alpha-hydroxysteroid-dehydrogenase activity was found to be increased after estrogen treatment, both in vivo and in vitro. These findings suggest that testicular 17alpha-hydroxylase activity (and possibly also 17-20 lyase activity) is either under gonadotropin regulation, or is directly suppressed by estrogen. This could result by decreased enzyme synthesis, direct enzyme inhibition or affectation of the cofactors or cytochromes necessary for the enzymatic activity. 20alpha-reduction of C21-steroids would represent an alternative pathway for their catabolism, not regulated by gonadotropin or not affected by estrogen, that would be significant in situations with reduced 17alpha-hydroxylase activity.

Adult↗
PubMed1980

A sensitive solid phase enzymeimmunoassay for norethisterone (norethindrone) in saliva and plasma.

A sensitive, solid phase enzymeimmunoassay suitable for determining norethisterone in small aliquots of plasma (10 microliters) and saliva (100 microliters) has been developed. A solid phase antiserum raised against a norethisterone-11 alpha-hemisuccinyl/bovine serum albumin conjugate was prepared by coupling to cyanogen bromide activated cellulose. A norethisterone/horseradish peroxidase conjugate was used as enzyme label, o-phenylenediamine/hydrogen peroxide being the substrate for colour development. The assay had a lower limit of sensitivity of 3 pg/assay tube and satisfied accepted validation criteria. Norethisterone concentrations determined by enzymeimmunoassay and by a well established radioimmunoassay were in excellent agreement in both plasma (r = 0.993, n = 20) and saliva (r = 0.989, n = 15). Plasma and salivary norethisterone concentrations determined in healthy volunteers reached peak values at about 1 hour after administering a norethisterone-containing oral contraceptive preparation. The maximum values achieved in saliva (775--1430 pmol/l) were only approximately 3% of those observed in plama. Since salivary norethisterone concentrations reflected those in plasma, they may be useful in fertility control programmes and pharmacokinetic studies.

Administration, Oral↗
PubMed1989

Serum progesterone and norethisterone levels following injection of norethisterone enanthate in different sites and doses.

Serum progesterone (P) and norethisterone (NET) levels following injection of norethisterone enanthate (NETEN) were studied in 11 regularly menstruating women. In 6 subjects 200 mg NETEN was administered to the gluteal (IG) or deltoid (ID) region sequentially. The serum P levels remained anovulatory (less than 4 ng/mL) up to 12 weeks. Serum NET levels were similar whether injection was given IG or ID (paired t - test, NS). In 5 subjects given a 150-mg dose, serum P levels remained anovulatory up to 11 weeks. Serum NET levels declined faster than with the 200-mg dose, but the difference was not significant (Student's t - test, NS). Wide inter-subject variations were seen in both groups. NETEN therefore can effectively be administered in gluteal or deltoid regions. A lower dose of 150 mg may have contraceptive potential on an 8-week schedule.

Adult↗