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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↗
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↗
PubMed1983

A rapid and sensitive radioimmunoassay for norethisterone.

A direct radioimmunoassay for the measurement of norethisterone (NET) in unextracted serum samples was developed. The combined use of a highly specific unpurified antiserum and heat treatment of diluted serum samples obviated both extraction and chromatographic procedures. The direct NET assay fulfilled all the quality control parameters. When this assay was compared with other methods involving either solvent extraction and/or chromatographic purification procedures, no significant differences were observed. The overall results were interpreted as demonstrating that this simple, rapid and reliable NET assay can be used as a helpful tool in metabolic and pharmacokinetic studies of this contraceptive progestogen.

Norethindrone↗
PubMed1983

Long-acting contraceptive agents: esters of norethisterone with alpha- and/or beta-chain branching.

The synthesis of eighteen esters of norethisterone (17 alpha-ethynyl-17 beta-hydroxyestr-4-en-3-one) is described. These all possess some form of alpha- and/or beta-substitution in the ester side-chain. The work was undertaken in order to evaluate any long-acting fertility control effect intrinsic in such compounds. A pentamethyl disiloxy ether was also included in the group of substances prepared for testing because of its similar substitution pattern.

Esters↗
PubMed1983

Long-acting contraceptive agents: norethisterone esters of arylcarboxylic acids.

The synthesis of esters of norethisterone (17 alpha-ethynyl-17 beta-hydroxy-estr-4-en-3-one) with acids containing a benzene ring is described, two methods of esterification being compared in terms of yield and convenience. The activities of these esters as long-acting contraceptive agents have been evaluated.

Carboxylic Acids↗
PubMed1983

Long-acting contraceptive agents: analysis and purification of steroid esters.

More than 200 samples of esters of norethisterone (17 alpha-ethynyl-17 beta-hydroxyestr-4-en-3-one) and levonorgestrel (13 beta-ethyl-17 alpha-ethynyl-17 beta-hydroxygon-4-en-3 -one) have been analysed by a combination of techniques, including high performance liquid chromatography (HPLC). Compounds having a purity below the required limit (99.5%) were purified, mainly by preparative HPLC, prior to formulation and biological evaluation as long-acting progestogens.

Chromatography, High Pressure Liquid↗
PubMed1983

Long-acting contraceptive agents: structure activity relationships in a series of norethisterone and levonorgestrel esters.

A large number of esters of norethisterone (17 alpha-ethynyl-17 beta-hydroxyestr-4-en-3-one) and levonorgestrel (D-(-)-13 beta-ethyl-17 alpha-ethynyl-17 beta-hydroxygon-4-en-3-one) were synthesized and tested for biological activity. The test employed in these studies was the duration of estrus suppression in cycling mature rats. In the norethisterone series several esters exhibited duration of activity comparable to that of norethisterone enanthate. In the levonorgestrel series the butanoic, cyclobutylcarboxylic and cyclopropylcarboxylic esters were longer acting than medroxyprogesterone acetate (17 alpha-acetoxy-6 alpha-methylpregn-4-ene-3,20-dione) when prepared as aqueous microcrystalline suspensions.

Animals↗
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↗