Non-protein bound dienogest in serum and salivary dienogest in women taking the oral contraceptives Certostat and Valette

Dienogest (17 alpha-cyanomethyl-17-hydroxy-4,9-estradien-3-one) is the progestagen component of the oral contraceptives Certostat and Valette. In contrast to other 19-norsteroid progestagens like levonorgestrel, norethisterone, gestodene and 3-ketodesogestrel, dienogest does not bind to sexual hormone binding globulin (SHBG). The absent binding to SHBG results in a high portion of free, non-protein bound dienogest in serum. In female volunteers taking the oral contraceptives Certostat and Trisiston, the part of non-protein bound dienogest and levonorgestrel, respectively, in serum was determined by the method of centrifugal ultrafiltration. The portion of free dienogest was found to be 9.55 +/- 0.95% (m +/- SD, n = 13) of total serum dienogest. Free levonorgestrel constituted 0.97 +/- 0.14% (n = 12) of total serum levonorgestrel. In an investigation with 47 female volunteers taking Certostat, serum total dienogest was quantified by a specific radioimmunoassay and free dienogest in serum by centrifugal ultrafiltration. In the serum samples with dienogest concentrations in the range of 4.1-57.7 ng/ml, the part of free, non-protein bound dienogest was found to be 8.90 +/- 0.54% of serum total dienogest. There is a high correlation between serum total dienogest and free dienogest (r = 0.989). In another investigation with 20 female volunteers taking the contraceptive Valette, serum total dienogest and salivary dienogest were quantified by radioimmunoassay and free dienogest in serum by centrifugal ultrafiltration. In the serum samples with dienogest concentrations in the range of 7.5-50.6 ng/ml, the part of free, non-protein bound dienogest was 8.78 +/- 0.77% of serum total dienogest. Salivary dienogest constituted 7.99 +/- 0.94% of serum total dienogest showing a high correlation with serum free dienogest (r = 0.953) and serum total dienogest (r = 0.958). The high portion of non-protein bound compound in serum is a characteristic pharmacokinetic feature of dienogest.

Studies on the hydrogenation of the progestagen dienogest in vivo and in vitro in the female rabbit

The biotransformation of the progestagen dienogest (17 alpha-cyanomethyl-17 beta-hydroxy-4,9-estradien-3-one) was studied in vivo in female rabbits and in vitro by liver homogenates from female rabbits and rats. In vivo, in the female rabbit, 3H-dienogest was the subject of an extensive biotransformation. A significant difference between the composition of the urinary and biliary metabolite patterns of dienogest was found. While in the urinary metabolite pattern more polar metabolites dominated, in bile of animals with a bile fistula, a dienogest metabolite of medium polarity was prevalent. This main metabolite of dienogest was identified by MS, 1H- and 13C-NMR spectroscopy and CD measurement of an enzymatic dehydrogenation product as the tetrahydro metabolite 17 alpha-cyanomethyl-5 alpha-estr-9-en-3 beta,17 beta-diol. Thus, in vivo, the 4,9-dien-3-oxo-19-norsteroid dienogest is hydrogenated to a 5 alpha H-9-en metabolite. In vitro, however, 3H-dienogest was only poorly transformed by liver homogenates from both species, whereas 3H-levonorgestrel and 3H-3-keto-desogestrel were converted partially by liver homogenates from female rabbits and completely by liver homogenates from female rats. The principal biotransformation reactions of levonorgestrel and 3-ketodesogestrel were the reduction of the 3-oxo group to 3-OH and the 5 beta- and 5 alpha-hydrogenation of the 4-double bond by homogenates of female rabbit liver and female rat liver, respectively. A dihydro metabolite of dienogest, in which the 3-oxo group had been reduced to 3-OH, was isolated in small amounts from the incubation with rabbit liver homogenate. The data indicate that the enzymatic hydrogenation of the 4-double bond of the 4,9-dien-3-oxo steroid dienogest is inhibited in vitro. The hindered hydrogenation reaction in vitro has to be seen in association with the 9-double bond in the steroid molecule.

Preparation of 3-ketodesogestrel metabolites by microbial transformation and chemical synthesis

Specific microbial reactions were used for the preparation of metabolites of 3-ketodesogestrel (13-ethyl-17 beta-hydroxy-11-methylene-18,19-dinor-17 alpha-pregn-4-en-20-yn-3-one, the active from of the progestagen desogestrel. Clostridium paraputrificum transformed 3-ketodesogestrel (KDG) to the 5 beta-dihydro and tetrahydro metabolites 13-ethyl-17 beta-hydroxy-11-methylene-18,19-dinor-5 beta, 17 alpha-pregnan-20-yn-3-one and 13-ethyl-11-methylene-18,19-dinor-5 beta, 17 alpha-pregnan-20-yne-3 alpha, 17 beta-diol, respectively. The epimeric compound 13-ethyl-11-methylene-18,19-dinor-5 beta, 17 alpha-pregnan-20-yne-3 beta, 17 beta-diol was obtained by chemical reduction of the 3-oxo compound. Mycobacterium smegmatis converted KDG to metabolites of the 5 alpha H-series: 13-ethyl-17 beta-hydroxy-11-methylene-18,19-dinor-5 alpha, 17 alpha-pregnan-20-yn-3-one, 13-ethyl-11-methylene-18,19-dinor-5 alpha, 17 alpha-pregnan-20-yne-3 alpha, 17 beta-diol and 13-ethyl-11-methylene-18,19-dinor-5 alpha, 17 alpha-pregnan-20-yne-3 beta, 17 beta-diol. The ring A-aromatized analog of KDG 13-ethyl-11-methylene-18,19-dinor-17 alpha-pregna-1,3,5(10)-trien-20-yne-3,17 beta-diol was obtained by microbial 1-dehydrogenation with Rhodococcus rhodochrous. Additionally, chemical syntheses of the microbially obtained KDG metabolites listed above were carried out. These included Birch reduction, reduction of KDG with sodium borohydride in aqueous pyridine and in methanol, reduction of KDG with potassium selectride in tetrahydrofuran, and dehydrogenation of KDG with cupric-II bromide in acetonitrile. The problems encountered in chemical syntheses favor the microbial procedures. The compounds were characterized by mass spectra (MS), IR, and circular dichroism (CD). Complete assignments of 1H and 13C chemical shifts were made using homo- and heteronuclear 2-DN-NMR spectroscopy. Chromatographic [gas-liquid chromatography (GLC), high-performance liquid chromatography (HPLC), thin-layer chromatography (TLC)] data of all the prepared KDG metabolites are presented.

Sequential appearance and ultrastructure of amphophilic cell foci, adenomas, and carcinomas in the liver of male and female rats treated with dehydroepiandrosterone

Dehydroepiandrosterone (DHEA), a hormone of the adrenal cortex, acts as a peroxisome proliferator and hepatocarcinogen in rats upon long-term treatment with high doses in the diet. The aim of the present study was to identify the site of origin of hepatocellular neoplasms and the sequence of preneoplastic lesions. Twenty-five female and 25 male rats were given 0.6% DHEA in the diet; 25 animals of each sex were controls. Groups of 5 treated and untreated animals were sacrificed after 4, 20, 32, 70, and 84 wk. Amphophilic cell foci were detected after 32 wk of treatment; they developed from the liver parenchyma almost exclusively in the vicinity of portal tracts. Adenomas of the amphophilic or amphophilic/tigroid cell phenotype were observed at 70 wk of treatment. Highly differentiated hepatocellular carcinomas presenting a similar cellular phenotype occurred after 70-84 wk. The incidence of hepatocellular carcinomas was 44% in female and 11% in male rats. Ultrastructural studies of the amphophilic cell foci and tumors revealed a marked proliferation of mitochondria and a moderate proliferation of peroxisomes in all lesions. In addition, a very strong peroxisome proliferation was observed in perivenular hepatocytes in the liver of female rats. Peroxisomes usually lacked core and showed flocculent matrices. In male rats, weak peroxisomal proliferation was observed. Typical morphological abnormalities of these peroxisomes were paracrystalline inclusions of striated appearance. Although the most prominent peroxisome proliferation was observed in perivenular hepatocytes, these cells did not seem to be involved in tumor development. In contrast, the morphological similarity of the amphophilic cell foci and the amphophilic/tigroid cell adenomas and carcinomas, their coincident localization near portal tracts, and the sequential appearance of these lesions suggest that the amphophilic cell foci represent an early stage in DHEA-induced hepatocellular neoplasia. Mitochondrial proliferation as the most prominent feature in all stages of this model of hepatocarcinogenesis may offer a new approach for analysis of hepatocarcinogenesis induced by DHEA and possibly other peroxisomal proliferators.

Sex differences in dehydroepiandrosterone metabolism in the rat: different plasma levels following ingestion of DHEA-supplemented diet and different metabolite patterns in plasma, bile and urine

Plasma dehydroepiandrosterone (DHEA) and DHEA sulfate levels were determined by an enzyme immunoassay in male and female Sprague-Dawley rats fed a diet containing 0.6% or 0.3% DHEA. A significant difference in DHEA plasma levels was observed in male and female animals. In male rats, total DHEA plasma concentrations were found in the range of 0.4-1.5 microgram/ml (0.6% DHEA chow) and 0.3-0.5 microgram/ml (0.3% DHEA chow). In female animals several times higher DHEA plasma levels were determined: 17.5-33 micrograms/ml (0.6% DHEA chow) and 8.3-14.8 micrograms/ml (0.3% DHEA chow). DHEA was present in rat plasma of both sexes preferably as the sulfate conjugate. Significant sex differences were also found in the DHEA metabolite patterns obtained by TLC separation of extracts from plasma, bile and urine following administration of 3H-DHEA. In female rats, DHEA is present predominantly as the sulfate conjugate in considerable amounts in all materials investigated, whereas in male rats polar metabolites dominate in the patterns.

Studies on the biotransformation of the progestagen dienogest in the rabbit

Following administration of 14 alpha, 15 alpha-3H-Dienogest (STS 557, 17 alpha-cyanomethyl-17 beta-hydroxy-4, 9-estradien-3-one) to female rabbits, extracts from urine, bile and plasma were separated by means of HPLC. Urinary and biliary metabolites are characterized by patterns of high complexity. From the mass spectra and UV absorption data of the urinary Dienogest metabolites a variety of biotransformation reactions has been derived like: hydroxylation in different positions of the Dienogest molecule, among these the 11-position; reduction of the 3-oxo group to 3-hydroxy; introduction of 2 and 4 hydrogen atoms; aromatization of ring A; transformation of 17 alpha-CH2CN to CH2OH, and formation of compounds with a 5(10), 9(11)-diene structure. Some of these reactions occur simultaneously resulting in a very complicated metabolite spectrum. Possibly the multiple effects of Dienogest established in animals are partially caused by metabolites.

Pharmacokinetics of the progestin dienogest (STS 557) in rabbits

Disposition and excretion of the progestin Dienogest (17 alpha-cyanomethyl-17 beta-hydroxy-estra-4,9-dien-3-one, STS 557) were investigated in female rabbits. Following single and repeated administration of the tritium-labelled compound the plasma concentration courses of total radioactivity (Dienogest + metabolites) and of the parent drug alone were estimated and also the urinary and fecal excretion of total radioactivity. From these data basic pharmacokinetic parameters were calculated. Additionally, the enterohepatic recirculation of biliary excreted metabolites was studied using bile of donors for oral administration to recipients. Following oral administration the high bioavailability of Dienogest which was already found in other animal species and in man could also be confirmed with rabbits. The parameters of Dienogest disposition do not differ significantly from those of the progestin levonorgestrel. Thus, the different effects of the both progestins in the McPhail-Clauberg assay in the rabbit cannot be attributed to differences in pharmacokinetics.

[Radioimmunologic determination of the progestagen dienogest in plasma and saliva]

Following oral administration of 2 mg of dienogest (17 alpha-cyanomethyl-17 beta-hydroxy-4,9-estradien-3-one) to female volunteers, the dienogest concentration courses in plasma and saliva were determined by means of a specific radioimmunoassay (RIA). Three different procedures of the plasma sample preparation prior to the RIA were compared. The dienogest RIA was directly applied to saliva. There is a high correlation between the dienogest concentrations in plasma and saliva. The dienogest plasma elimination half life of about 9 hrs is not significantly different from that derived from saliva. The salivary dienogest concentrations indicate a relatively high non-protein bound portion of this steroid drug in plasma. Following repeated oral administration of dienogest (tau = 24 hrs), there is no significant cumulation of plasma dienogest.

[Radioimmunoassay of the progestagen dienogest using various methods of sample preparation of plasma]

For the radioimmunological determination (RIA) of the progestagen dienogest (1, 17 alpha-Cyanomethyl-17 beta-hydroxy-estra-4,9-dien-3-one) in plasma three methods of sample preparation were tested and compared: Extraction of plasma samples with dichlormethane (I), binding of plasma dienogest to an antiserum added; removal of non-bound steroids by means of activated charcoal, extraction of dienogest using dichlormethane (II), using the RIA without extraction of plasma samples after partial precipitation of proteins by means of ammonium sulphate (III). The reliability of the dienogest-RIA is, characterized by a limit of detection of 3.2 pg (I, III) and 5 pg (II) per tube, respectively, by "within-assay"- and "between-assay" variation coefficients of 3 to 5% and 3 to 9%, respectively, in parallel determinations and by a high rate of recovery of dienogest (greater than 90%) added to plasma. The application of the parallelism test method to different plasma volumes confirms the accuracy of method I and II. When method III was applied to plasma samples with low concentrations of dienogest parallelism wasn't found in all cases.

[Bovine serum albumin conjugates of the new progestagen dienogest, synthesis and immunogenic properties]

In order to develop a radioimmunoassay for the new progestagen dienogest (STS 557, 17 alpha-cyanomethyl-17 beta-hydroxy-estra-4,9-dien-3-one), bovine serum albumin (BSA) conjugates of STS 557-3-carboxymethyloxime and of STS 557-11-hemisuccinate were synthesized as antigens for the production of antisera. It was proved that an excess of isobutylchlorocarbonate in the coupling reaction using the "mixed anhydride method" results in an acylation of free NH2-groups in the BSA. By the immunization of rabbits with the STS 557-antigen-antisera of high specificity and affinity to STS 557 were produced. Endogenous steroids show no cross reaction with the STS 557-antisera. Steroids with a 17 alpha-CH2CN-group, being obtained by chemical synthesis or microbial transformation, compete with STS 557 for the binding positions of the antibodies to a different extent.

Studies on pharmacokinetics of STS 557 in animal species and man

Following oral and i.v. administration of [14 alpha, 15 alpha-3H]-STS 557 to beagle dogs, baboons, rats and female volunteers, plasma level courses of total radioactivity and STS 557, and radioactivity excretion in urine and feces have been investigated. Bioavailability of orally administered STS 557 was found to be 80--90% in man and beagle dog, 70--80% in baboon and rat. Concerning the systemic availability following oral administration of equivalent doses, the following order was established: beagle dog greater than man greater than baboon greater than rat. Equilibrium dialysis indicates species differences in plasma protein binding and a considerable part of STS 557 to be present in plasma unbound. STS 557 is rather rapidly eliminated from the plasma compartment of all species investigated with half lives less than or equal to 10 h. As an additional time parameter of pharmacokinetics the "mean residence time" was used. Urinary excretion of STS 557 metabolites is dominant in all species, including the rat. In contrast to the great part of STS 557 in plasma total radioactivity, only small amounts of unchanged STS 557 are excreted in urine. First results of current studies in rabbits are presented, too.

Studies on biotransformation of STS 557

Transformation of STS 557 (17 alpha-cyanomethyl-17 beta-hydroxy-estra-4, 9-dien-3-one) by female rat liver microsomes demonstrates a lower transformation rate in comparison with the analogous compound without 9-double bond: 17 alpha-cyanomethyl-19-nortestosterone, and the basic substance: 19-nortestosterone. 17 alpha-Cyanomethyl-estra-1, 3, 5(10), 9(11)-tetraene-3, 17 beta-diol, 17 alpha-cyanomethyl-11 beta, 17 beta-dihydroxy-estra-4, 9-dien-3-one, and tentatively 17 alpha-cyanomethyl-6 alpha, 17 beta-dihydroxy-estra-4, 9-dien-3-one were identified as metabolites. Microbial model investigations with species known to hydrogenate the 4-double bond in 4-en-3-oxo steroids stereospecifically to 5 alpha H- or 5 beta H-metabolites indicate 5 alpha-hydrogenation to be prevented in STS 557 by the 9-double bond, whereas 5 beta-hydrogenation is not affected. Isolation and characterization of metabolites from beagle dog and rat urine following administration of 3H-STS 557 revealed the following pathways of biotransformation: Hydroxylation in different positions of the steroid molecule, aromatization of ring A, hydrogenation of a double bond, simultaneous hydroxylation and hydrogenation, and alteration of the 17 alpha-side chain with loss of nitrogen.

Urinary metabolites of the new progestagen STS 557 (17 alpha-cyanomethyl-17-hydroxy-4,9-estradien-3-one) in the dog and rat

Urinary metabolites of the new progestagen STS 557 (17 alpha-cyanomethyl-17-hydroxy-4,9-estradien-3-one) were isolated and characterized following oral administration of the 14 alpha, 15 alpha-tritium labelled compound to dogs and rats. 17 alpha-Cyanomethyl-11 beta, 17-dihydroxy-4,9-estradien-3-one (11 beta-OH-STS 557) and 17 alpha-cyanomethyl-1,3,5(10),9(11)-estratetraene-3,17-diol were identified by comparison with synthesized reference compounds. Mass spectra data indicate the following other pathways of STS 557 biotransformation: Hydroxylation in other positions than 11; hydrogenation; hydroxylation + hydrogenation; alteration of the 17 alpha-side chain.

Microbial transformation of 17 alpha-cyanomethyl-17-hydroxy-4,9-estradien-3-one (STS 557) and 17 alpha-cyanomethyl-19-nortestosterone by Mycobacterium smegmatis

Microbial transformation of the new progestagen STS 557 (17 alpha-cyanomethyl-17-hydroxy-4,9-estradien-3-one) by Mycobacterium smegmatis yielded predominantly ring A-aromatized compounds: 17 alpha-cyanomethyl-1,3,5(10),9(11)-estratetraene-3, 17-diol, 17 alpha-cyanomethyl-1,3,5(10)-estratriene-3,17-diol and the corresponding 3-methyl ethers. The analogous compound without the 9(10) double bond, 17 alpha-cyanomethyl-19-nortestosterone, was transformed mainly to 5 alpha-hydrogenated metabolites: 17 alpha-cyanomethyl-17-hydroxy-5 alpha-estran-3-one, 17 alpha-cyanomethyl-17-hydroxy-5 alpha-1-estren-3-one, 17 alpha-cyanomethyl-5 alpha-estrane-3 alpha, 17-diol, and 17 alpha-cyanomethyl-5 alpha-estrane-3 beta, 17-diol. From these results, it is concluded that 4,9-dien-3-oxo compounds are not substrates for enzymatic 5 alpha-hydrogenation.

Species differences in biotransformation of 17 alpha-cyanomethylestradiol 3-methyl ether

Following oral administration of 9,11-3H-17 alpha-cyanomethylestra-1,3,5(10)-triene-3,17-diol 3-methyl ether, urinary metabolites were studied in man, baboon, beagle dog, minipig and rat. The metabolite pattern revealed remarkable species differences, especially in quantitative respects. 17 alpha-Cyanomethylestra-1,3,5(10)triene-3,17-diol, 17 alpha-cyanomethylestra-1,3,5(10)-triene-2,3,17-triol 2-methyl ether, 17 alpha-hydroxymethylestra-1,3,5(10)-triene-3,17-diol and 17 alpha-cyanomethylestra-1,3,5(10)-triene-3,16 xi, 17-triol were isolated as principal metabolites. In rat bile, a metabolite was tentatively identified as a gamma-lactone of a 17 alpha-carboxymethyl-16 alpha-hydroxy compound.

[Steroid metabolism in primates. XX. Excretion of C21-steroids in urine of women and baboons (Papio hamadryas) during pregnancy]

Urinary excretion of 10 C21 steroids was investigated in women and baboons (Papio hamadryas) in various stages of pregnancy, in comparison to controls. In pregnant women, excretion of total C21 steroids is slightly increased, whereas in pregnant baboons it is slightly decreased. In women, excretion of tetrahydrocortisol and tetrahydrocortisone is diminished, that of 20 beta-OH-F (11-beta,17alpha,20beta,21-tetrahydroxy-4-pregnen-3,20-dione) and of 11-deoxycortisol is increased. In pregnant baboons no significant alterations in corticosteroid metabolism were established.

[Steroid metabolism in primates. XIX. Urinary excretion of C21-steroids in Cercopithecus aethiops and Erythrocebus patas]

In male Cercopithecus aethiops (green monkey; grivet) and Erythrocebus patas (dancing red monkey; patas monkey), the pattern of urinary C21 steroids was estimated and compared with those of man, baboon and rhesus monkey. The results indicate diminished 11 beta- and 17 alpha-hydroxylation in steroid biosynthesis as well as diminished delta 4-3-keto reduction and increased 20 beta-reduction in metabolism in these two species.

[Steroid metabolism in primates. XVIII. Return to higher levels of 17-ketosteroid excretion in urine after ending a long-term treatment with mestranol/chlormadinone acetate in the baboon]

6 weeks after terminating a long-time application of the ovulation inhibitor Ovosiston (mestranol/chlormadinone acetate) in female baboons, excretion of 17-ketosteroids in urine is still decreased. 6 months after ceasing the preparation, urinary 17-ketosteroid excretion resembles that of the control group.

[Metabolism of sulfate and phosphate conjugates of 19-nortestosterone enantiomers]

The sulfate and phosphate conjugates of 19-nortestosterone (17beta-hydroxy-estr-4-ene-3-one) and ent-19-nortestosterone (ent-17beta-hydroxy-estr-4-ene-3-one) have been synthesized. The sodium salts of the conjugates were i.v. infused to 2 women. On days 1--4 following application, the 19-nortestosterone and 17-ketosteroid excretion in urine as well as the 19-nortestosterone conjugation have been estimated. The 19-nortestosterone enantiomers were excreted in nearly the same amounts. In comparison to testosterone, the excretion of unchanged steroid (20--50%) is significantly higher. The sulfate conjugates of the enantiomers are not hydrolyzed in vivo, whereas the phosphate conjugates are completely splitted. Hydrolysis of ent-nortestosterone phosphate takes place obviously more slowly. Urinary 17-ketosteroids are significantly increased only following infusion of 19-nortestosterone phosphate.

[Steroid metabolism in primates. XVII. Isolation of 17alpha-hydroxy-pregnenolone from adrenal venous blood of the baboon (Papio hamdryas)]

17alpha-Hydroxypregnenolone (3beta,17alpha-dihydroxy-5-pregene-20-one) was isolated from adrenal venous blood of male healthy baboons and identified by paper chromatography, thin layer chromatography and infrared spectrometry. In 6 animals the concentration in adrenal venous blood (16--70 mug/100ml) and the secretion rate (2--5 mug/h/kg body weight) have been estimated. The results demonstrate the secretion of 17alpha-hydroxypregnenolone by the baboon adrenal.