Determination of rat 5alpha-reductase type 1 isozyme activity and its inhibition by novel steroidal oxazolines.

The 5alpha-reductase type 1 isozyme is a key enzyme in the metabolism of the androgen steroid hormones and inhibitors of this enzyme represent a new pharmacological treatment for several androgen dependent diseases. We developed a radiosubstrate in vitro incubation method for the determination of 5alpha-reductase type 1 activity using rat liver microsomes as an enzyme source. With this method we have studied the inhibiting activity of novel (5' S)-17beta-(4,5-dihydrooxazol-5-yl)androst-5-en-3-one compounds containing various derivatized phenyl substituents coupled to the exo -heterocyclic moiety. Tests revealed moderate inhibitory actions compared to finasteride, nevertheless, results provide interesting structure-activity relationship data.

Configurational analysis and relative binding affinities of 16-methyl-5alpha-androstane derivatives.

The four possible isomers 16beta-hydroxymethyl-5alpha-androstane-3beta,17beta-diol 1, 16alpha-hydroxymethyl-5alpha-androstane-3beta,17beta-diol 2, 16beta-hydroxymethyl-5alpha-androstane-3beta,17alpha-diol 3 and 16alpha-hydroxymethyl-5alpha-androstane-3beta,17alpha-diol 4 with proven configuration were converted into the corresponding 16beta-methyl-5alpha-androstane-3beta,17beta-diol 5, 16alpha-methyl-5alpha-androstane-3beta,17beta-diol 6, 16beta-methyl-5alpha-androstane-3beta,17alpha-diol 7, 16alpha-methyl-5alpha-androstane-3beta,17alpha-diol 8, furthermore into the 16beta-methyl-17beta-hydroxy-5alpha-androstane-3-one 13, 16alpha-methyl-17beta-hydroxy-5alpha-androstan-3-one 14, 16beta-methyl-17alpha-hydroxy-5alpha-androstan-3-one 15 and 16alpha-methyl-17alpha-hydroxy-5alpha-androstan-3-one 16. The steric structures of the resulting epimers were determined by means of 1H-, and 13C-NMR spectroscopy. In this way, comparison was possible with the C-16 epimers 5, 6 and 13, 14 prepared earlier by a different route, and the series of isomers could be completed with the steric structures of 16beta-methyl-17alpha-hydroxy-5alpha-androstan-3beta-ol 7 and 16alpha-methyl-17alpha-hydroxy-5alpha 8 and with their 3-keto derivatives 15 and 16. The relative binding affinities of the 16-methyl-5alpha-androstane-3beta,17-diols 5, 6, 7, 8 and 17-hydroxy-16-methyl-5alpha-androstan-3-ones 13, 14, 15, 16 were studied. The introduction of a 16-methyl substituent into 5alpha-androstane molecules substantially decreases the binding affinity to the androgen receptor and 16alpha-methyl derivatives were always bound more weakly than the 16beta-methyl isomers.

Neighboring group participation. Part 14. The preparation of the four stereoisomers of 16-hydroxymethyl-5alpha-androstane-3beta,17-diol.

16alpha-Hydroxymethyl-5alpha-androstane-3beta,17beta-diol and 16beta-hydroxymethyl-5alpha-androstane-3beta,17beta-diol, were obtained from reduction of 16-acetoxymethylene-5alpha-androstan-17-one. The corresponding 16alpha,17alpha- and 16beta,17alpha-hydroxymethyl isomers were obtained by neighboring group participation of the 16- and 17-acetates, respectively. The reactions involving carbocation formation also led to ring D rearrangement products.

[Synthesis of estrone derivatives containing different halogens and/or heterocyclic moieties]. / Halogéntartalmú és heterociklusos ösztronszármazékok szintézise.

New compounds derived from the 3-methyl and 3-benzyl ethers of a D-secoestrone aldehyde were synthesized. In the presence of different Lewis acids D-homosteroids could form. These reactions which can be explained by an intramolecular Prinstype mechanism follow high stereoselectivity and reactivity and lead to compounds containing 16 beta-oriented halogens in the sterane skeleton. The formation and reaction of the imines derived from the aldehyde and aniline as well as substituted anilines provide a highly efficient access to steroid derivatives. The steroid alkaloids are of pharmacological interest.

A novel approach in drug discovery: synthesis of estrone--talaromycin natural product hybrids.

Hetero-Diels-Alder reaction of the steroidal exocyclic enol ethers 14 and 15, obtained from the secoestrones 8 and 9 by reduction, iodoetherification, and elimination, with ethyl O-benzoyldiformylacetate (16) leads to the spiroacetals 17 and 18 as a mixture of four diastereomers. Reduction of the major diastereomers 17a and 18a with DIBAH and subsequent hydrogenation yields the novel natural product hybrids 21, 23, 24, and 25, which possess the structural features of the steroid estrone (7) and the mycotoxin talaromycin 6.

High-performance liquid chromatographic methods for monitoring of isomers of 17-hydroxy-16-hydroxymethyl-3-methoxyestra-1,3,5(10)-triene.

Claisen condensation and consecutive reduction of 3-methoxyestra-1,3,5(10)-trien-17-one theoretically leads to four diastereomers of 17-hydroxy-16-hydroxymethyl-3-methoxyestra-1,3,5(10)-triene and their further transformations give different compounds with different biological activities. High-performance liquid chromatographic methods were developed for separation of the four isomers of 17-hydroxy-16-hydroxymethyl-3-methoxyestra-1,3,5(10)-triene: reversed-phase separation on a Nucleosil ODS C18 column with water-methanol as mobile phase; and normal-phase separation on an APEX Silica column with hexane-dichloromethane-2-propanol as mobile phase. The effects of eluent composition and flow-rate on the separation were investigated. This is the first chromatographic evidence for the formation of the 16alpha,17alpha isomer in the reduction of 16-hydroxymethylene-3-methoxyestra-1,3,5(10)-trien-17-one.

The ursodeoxycholic acid-p-aminobenzoic acid deconjugation test, a new tool for the diagnosis of bacterial overgrowth syndrome.

OBJECTIVE: To determine the possible complementary role of the ursodeoxycholic acid-p-aminobenzoic acid (UDCA-PABA) loading test in the diagnosis of intestinal bacterial overgrowth. DESIGN: A prospective clinical study. PATIENTS AND METHODS: The hydrogen breath and UDCA-PABA tests were performed simultaneously in 68 patients with suspected contaminated small bowel syndrome (CSBS), and in 10 healthy control subjects. The hydrogen breath test was performed by oral loading of 25 g of lactose and/or 10 g of lactulose. The UDCA-PABA test was carried out by oral loading of 250 mg of UDCA-PABA conjugate, followed by measurement of the amount of PABA excreted in the urine. The diagnosis of bacterial overgrowth was considered to be established when either the hydrogen breath test or the UDCA-PABA test produced abnormal results. RESULTS: Thirty-five of the 68 patients proved to have CSBS. In 13 of these 35 patients, only the enhanced urinary PABA excretion (11.7 +/- 1.42 mg vs. 3.6 +/- 0.68 mg) indicated bacterial overgrowth, 15 of the 35 patients gave only a positive hydrogen breath test, and in the remaining seven cases the results of both tests were abnormal. In eight CSBS patients, the urinary excretion of PABA was decreased significantly following 10-day tinidazole treatment (5.5 +/- 1.29 mg vs. 13.1 +/- 2.07 mg). CONCLUSION: The UDCA-PABA test is a valuable clinical method for the detection of bacterial overgrowth, especially in cases where hydrogen production alone fails to reveal CSBS. It is also a useful procedure for evaluating the efficacy of antibacterial treatment.

[The ursodeoxycholic acid-p-aminobenzoic acid test in the diagnosis of small bowel bacterial overgrowth syndrome]. / Az ursodezoxikólsav-p-aminobenzoesav teszt a kontaminált vékonybélszindróma diagnosztikájában.

UNLABELLED: Contaminated small bowel syndrome is frequently associated with meteorism due to excessive gas formation, and diarrhoea as a result of bacterial fermentative processes, including splitting of carbohydrates or deconjugating and dehydroxylating bile salts. In addition to gas production, bacteria capable of metabolizing bile salts have been shown to release p-aminobenzoic acid (PABA) from and Ursodeoxycholic-acid-PABA substrate. Our aim was to determine the possible complementary role of the UDCA-PABA test in the diagnosis of bacterial overgrowth. PATIENTS AND METHODS: The H2 breath and UDCA-PABA tests were performed simultaneously on 46 patients with suspected contaminated small bowel syndrome, and on 7 healthy subjects. The H2 breath test was performed by oral loading of 25 g lactose and/or 10 g lactulose. The UDCA-PABA test was carried out by determining urinary excretion of PABA after oral loading with 250 mg UDCA-PABA conjugate. The diagnosis of bacterial overgrowth was established, when either H2 breath, or UDCA-PABA test proved to be pathological. RESULTS: Based upon the pathologic values of either the H2 breath test, or the UDCA-PABA test, 25 out of 46 patients proved to have contaminated small bowel syndrome. In 10 out of 25 patients only pathologic urinary PABA excretion (12.772 +/- 1.707 vs 4.1 +/- 0.58), indicated bacterial overgrowth, and in 9 out of the same group only positive H2 breath test (early rise of > 20 ppm of H2) indicated the same, while in 6 cases both tests proved to be pathological. In 7 CSBS patients the urinary excretion of PABA significantly decreased following a 10 day Tinidazole treatment (5.48 +/- 1.286 vs 13.068 +/- 2.068). CONCLUSION: The UDCA-PABA test proved to be a valuable complementary method to detect bacterial overgrowth, when H2 production failed to reveal bacterial overgrowth.

In vitro binding of 16-methylated C18 and C19 steroid derivatives to the androgen receptor.

The binding of androgens and structurally related analogues to the androgen receptor was studied. The in vitro experiments were carried out with cytosol of castrated rat prostate, using [3H]R1881 (methyltrienolone) as radioligand. The binding parameters measured were Kd = 1.25 x 10(-10) M and Bmax = 111 fmol (mg protein)-1. Ligand specificity was confirmed by competition experiments with known androgen, oestrogen and progestogen ligands. The receptor binding of substituted steroids was studied. The RBAs (relative binding affinities) of our recently synthetized 16-alkyl steroids were low. The only exception was the 17 beta-hydroxy-16 beta-methylestr-4-en-3-one, which exhibited the remarkable RBA of 22.9%.

In vitro inhibitory effects of 16-methyl-substituted steroids on 5 alpha-reductase in rat and human prostates.

The inhibitory effects (IC50) of 16-methyl steroids on 5 alpha-reductase were studied. The in vitro experiments were carried out with homogenates of rat and human prostates. The investigated 16-methyl steroids were found to be weak inhibitors. In comparison with the known 5 alpha-reductase inhibitor 4-MA (17 beta-N, N-diethylcarbamoyl-4-methyl-4-aza-5 alpha-androstan-3-one), the relative IC50 values of the studied compounds are 4.7 times or more greater than 4-MA in human prostate and 23.5 times or more greater than 4-MA in rat prostate. The IC50 values increase in the sequence 16 alpha-, 16 beta- and 16,16-dimethyl derivatives. In human prostate homogenates IC50 varies between 0.6 and 120, while in rat it ranges from 1.6 to 1000 microM. This shows that the enzyme of the human prostate is more sensitive than that of the rat prostate to the methyl-substituted compounds.

[In vitro inhibitory effects of 16-methyl-substituted steroids on 5 alpha-reductase in rat and human prostates]. / 16-metil-szubsztituált szteroidok in vitro gátló hatása az 5 alpha-reduktáz aktivitására patkány- és emberi prosztatában.

The inhibitory effects (IC50) of 16-methyl steroids on 5 alpha-reductase were studied. The in vitro experiments were carried out with homogenates of rat and human prostates. The investigated 16-methyl steroids were found to be weak inhibitors. In comparison with the known 5 alpha-reductase inhibitor 4-MA, the relative IC50 values of the studied compounds are 4.7 times or more greater than 4-MA in human prostate and 23.5 times or more greater than 4-MA in rat prostate. The IC50 values increase in the sequence 16 alpha, 16-beta- and 16,16-dimethyl derivatives. In human prostate homogenates IC50 varies between 0.6 and 120, while in rat it ranges from 1.6 to 1000 microM. This shows that the enzyme of the human prostate is more sensitive than that of the rat prostate to the methyl-substituted compounds. Acylation of the 17-hydroxy group significantly increases the IC50 values (cf. 8,11: from 4.8 to 23.5 and from 0.52 to 0.62;9,12: from 26.0 to 170.0 and from 0.58 to 1.4;15,17: from 3.9 to 35.0; and 16,18: from 5.6 to 58.0 microM). Whereas lack of a 19-CH3 group improves the inhibitory effect in the 16-unsubstituted compounds (1,19;14,22), the reverse hold in the 16-methylated derivatives (9,20; 10,21; 15,23; 16,24).

Synthesis of new 16-spirosteroids.

Reaction of estrone methyl ether 1 with sodium hydride and 1,3-dibromopropane, 1,4-dibromobutane, and 1,5-dibromopentane, respectively, gives the 16-spirosteroid derivatives 2-4, which were reduced to the 17 beta-alcohols 7-9. Acetylation afforded the acetates 10-12. In the reaction of 1 and 1,3-dibromopropane a bis-allyl compound 5 and an annulated dihydropyran 6 were also formed. Cleavage of the ether moiety in 2 and 3 was accomplished with diisobutylaluminum hydride to give 3,17 beta-diols 13 and 14, respectively.

Steroids 35: synthesis of 16,16-dimethyl-17 beta-hydroxysteroids.

The reaction of 16-methylene-17-ketosteroids (Ia), (Ic) and (Ie) with methyl magnesium iodide yields 16-methylene-17 alpha-methyl-17 beta-hydroxysteroids (IIa), (IIb) and (IId). These are subjected to the addition of hypobromous acid and the subsequent anionotropic rearrangement to convert them into 16 alpha-methyl-16 beta-bromomethyl-17-ketosteroids (Va), (Vb) and (Vd). These were reduced with LiA1H4 to obtain 16,16-dimethyl-17 beta-hydroxysteroids (VIa), (VIb) and (VId). Compounds (VIIa) and (VIIe) were selectively deacetylated yielding (VIIb) and (VIId); these were then oxidized and hydrolyzed to convert them into (VIf) and (VIg).

Steroids 36: synthesis of 16,16-dimethyl-17-ketosteroids and 16,16-dimethyl-17 beta-hydroxysteroids.

Direct conversion of 17-ketosteroids (Ia-f) into 16,16-dimethyl-17 beta-hydroxysteroids (IIa-f) and 16,16-dimethyl-17-ketosteroids (IIIa-f) was achieved with methyl iodide in the presence of NaH.