Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The objective of this investigation was to determine if decreased biosynthesis or increased catabolism of progesterone (P) during labor was responsible for the decreased concentration of hormone observed in the human placenta after labor and vaginal delivery. No significant difference was found in P biosynthesis by placental tissues examined before and after labor as evidenced by a similar activity of 3 beta-hydroxysteroid dehydrogenase: delta 5-isomerase. In contrast, there was a marked increase in P catabolism during labor, as shown by a significant (p less than 0.05) change in placental 20 alpha-hydroxysteroid oxidoreductase activity which increased from 835.5 +/- 103 (mean +/- SEM) pmoles of 20 alpha-dihydroprogesterone (20 alpha-DHP) generated per milligram of protein per hour before labor to 1,160.4 +/- 101 pmoles/mg/hr after labor. A similar significant (p less than 0.02) increase in enzyme activity was noticed in parallel assays of the reverse (20 alpha-DHP leads to P) reaction. As a consequence of increased P catabolism, placentas after labor had a 20 alpha-DHP concentration of 63.7 +/- 9.5 (mean +/- SEM) ng/mg protein, a value which was significantly (p less than 0.05) larger than that found before labor (37.8 +/- 8.3 ng/mg protein). These changes resulted in a modification of the placental tissue P/20 alpha-DHP ratio which decreased from 2/1 before to 1/1 after labor. The results indicate that the catabolism of P to 20 alpha-DHP increases significantly during human parturition. This phenomenon may be of importance in the mechanism of initiation and continuation of labor.
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PMID:20 alpha-Hydroxysteroid oxidoreductase activity and 20 alpha-dihydroprogesterone concentration in human placenta before and after parturition. 42 23

Androgen metabolism was investigated in normal human apocrine glands and in those isolated from age-matched patients with hidradenitis suppurativa. Axillary glands were isolated by shearing and androgen interconverting enzyme activities were measured in cell-free homogenates by incubation with [3H] dehydroepiandrosterone, [3H] androstenedione and [3H] testosterone. The activities (pmol/mg protein/min: mean + SEM) of 3 beta-hydroxysteroid dehydrogenase delta 4-5-isomerase (10.0 +/- 1.2 vs. 5.3 +/- 0.5: n = 5) and 17 beta-hydroxysteroid dehydrogenase (58.1 +/- 4.5 vs. 35.7 +/- 5.2: n = 5) were significantly lower (P less than 0.005) in hidradenitis suppurativa, whereas 5 alpha-reductase activity (12.5 +/- 2.3 vs. 12.5 +/- 2.0: n = 5) was similar. This report suggests that hidradenitis suppurativa cannot be attributed to exaggerated activities of end-organ androgen interconverting enzymes.
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PMID:Androgen metabolism by isolated human axillary apocrine glands in hidradenitis suppurativa. 195 17

To clarify the autoregulatory mechanism of progesterone (P) production in the ovulatory process, we examined the ovarian concentration of P 46 hrs after PMSG and the effects of P and RU486 (RU) injected 4-2 hrs before hCG administration on the serum concentrations of P and estradiol (E2), and ovarian 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) activities in PMSG/hCG treated immature rats. The effect of RU on the number of ovulated ova was also studied. The ovarian concentration of P 46 hrs after PMSG was 0.96 +/- 0.03,ng/mg protein (mean +/- SEM). When P (100,mg/kg) was injected 2 hrs before hCG, ovarian 3 beta-HSD activities had significantly increased by 4 hrs after hCG. However, P at a dosage of 10 and 20,mg/kg had no effect on ovarian 3 beta-HSD activities. The administration of RU (20,mg/kg) 2 hrs before hCG significantly inhibited ovarian 3 beta-HSD activities measured 4 and 6 hrs after hCG (p less than 0.01 and p less than 0.05, respectively). In addition, the serum P concentration 4 hrs after hCG was significantly lower than that of the control (p less than 0.01). However, RU (20 mg/kg) in concomitant with hCG had no effect on ovarian 3 beta-HSD activities within 6 hrs after hCG. The suppression of ovarian 3 beta-HSD activities by RU was the concomitant reversed by the concomitant treatment with P (10 mg/kg). RU (10, 20, or 40 mg/kg) injected 2 hrs before hCG significantly reduced the number of ovulated ova (p less than 0.01, p less than 0.01 and p less than 0.01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[The effect of progesterone and RU486 on progesterone production in the ovulatory process of rats]. 204

Ketoconazole, an orally active antifungal drug, is known to inhibit testicular androgen production both in vitro and in vivo. The aim of the present study was to examine the effect of ketoconazole and 13 other imidazole drugs on rat testicular microsomal 17 alpha-hydroxylase, 17,20-lyase, 3 beta-hydroxysteroid dehydrogenase-isomerase (3 beta-HSD-I) and 17 beta-hydroxysteroid oxidoreductase (17 beta-HSOR). The order of decreasing inhibitory effect (determined from Ki values) on 17 alpha-hydroxylase (substrate [3H]progesterone; Km = 89 +/- 0.65 nmol/l; SEM, n = 8) was bifonazole (Ki = 86 +/- 3.3 nmol/l; SEM, n = 4) greater than ketoconazole (160 +/- 4.92) greater than clotrimazole (170 +/- 5.81) greater than miconazole (599 +/- 7.22) greater than econazole (688 +/- 6.98) greater than tioconazole (901 +/- 1.71) greater than isoconazole (1090 +/- 6.96) and on 17,20-lyase (substrate, [3H]17 alpha-hydroxyprogesterone; Km = 250 +/- 0.75 nmol/l; SEM, n = 8) was bifonazole (56.5 +/- 3.4) greater than clotrimazole (81.5 +/- 3.1) greater than ketoconazole (84 +/- 3.5) greater than miconazole (243 +/- 6.3) greater than econazole (325 +/- 5.1) greater than tioconazole (505 +/- 5.2) greater than isoconazole (610 +/- 6.34). However, these imidazole drugs did not inhibit the 3 beta-HSD-I or 17 beta-HSOR activities. A common structural feature of the imidazole drugs having an inhibitory effect was the presence of one or more aromatic rings on the imidazole side chain. In contrast, the imidazole drugs having the imidazole ring fused to a benezene ring, i.e. benzimidazoles (astemizole, mebendazole, thiabendazole) and those having an aliphatic side chain on the N-1 of the imidazole ring (carbimazole, metronidazole, nimorazole, tinidazole) did not inhibit 17 alpha-hydroxylase, 3 beta-HSD-I or 17 beta-HSOR enzyme activities. However some did inhibit 17,20-lyase activity but only at high concentrations. The results of the present study suggest that some imidazole drugs may be useful in clinical situations requiring the suppression of androgen production, for example in the treatment of hormone-dependent prostatic cancer.
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PMID:Inhibition of testicular 17 alpha-hydroxylase and 17,20-lyase but not 3 beta-hydroxysteroid dehydrogenase-isomerase or 17 beta-hydroxysteroid oxidoreductase by ketoconazole and other imidazole drugs. 282 31

Hyperprolactinemic patients may have increases in plasma dehydroepiandrosterone (DHA) and dehydroepiandrosterone sulfate (DHAS). We examined the effect of lowering serum PRL with bromocriptine or pituitary surgery on the serum concentrations of adrenal androgens and on the production rate (PR) and MCR of DHAS in eight hyperprolactinemic women (HP). We also examined the effect of bromocriptine therapy on adrenal androgens in five normal men. Serum DHAS was elevated in HP compared to normal women (mean +/- SEM, 254 +/- 28 vs. 182 +/- 13 microgram/dl; P less than 0.04). Serum DHA and androstenedione (delta 4) in HP were not significantly different from normal. Serum PRL fell from 160 +/- 16 to 37 +/- 9 ng/ml during or after treatment. Mean 24-h serum DHAS fell from 198 +/- 30 to 106 +/- 17 micrograms/dl (P less than 0.001) with treatment, without a change in the mean 24-h serum cortisol concentration (6.2 +/- 0.4 vs. 6.6 +/- 0.4 micrograms/dl). Thus, the DHAS to cortisol (DHAS/F) ratio fell significantly (32 +/- 5 to 17 +/- 4; P less than 0.001). This was also true of the DHAS/F ratio during ACTH stimulation (8 +/- 1 to 6 +/- 1; P less than 0.02). Similar changes were found in basal and ACTH-stimulated DHA/F ratios, whereas the basal and ACTH-stimulated delta 4/F ratios did not change significantly with treatment. Treatment lowered the PR of DHAS from 27 +/- 5 to 17 +/- 3 mg/24 h (P less than 0.03) and increased the DHAS MCR from 16 +/- 2 to 21 +/- 3 liters/24 h (P less than 0.01). Bromocriptine treatment of normal men lowered serum PRL from 15 +/- 2 to less than 2.5 ng/ml. There were no significant changes in the basal and ACTH-stimulated serum DHAS/F, DHA/F, or delta 4/F ratios or DHAS PR and MCR during bromocriptine therapy. The failure of bromocriptine to significantly alter these steroids in normal men suggests that bromocriptine was not directly responsible for the changes in HP treated with this drug. A mechanism for the increased PR of DHAS in HP was sought by examining the serum concentrations of the steroid biosynthetic intermediates relevant to DHAS production. Lowering serum PRL was associated with a decrease in basal and ACTH-stimulated 17-hydroxypregnenolone/17-hydroxyprogesterone and DHA/delta 4 ratios, suggesting an increase in 3 beta-hydroxysteroid dehydrogenase/delta 4,5-isomerase activity. However, increased gonadal secretion of the delta 4-steroids may have occurred with the fall in serum PRL.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The effect of serum prolactin on plasma adrenal androgens and the production and metabolic clearance rate of dehydroepiandrosterone sulfate in normal and hyperprolactinemic subjects. 299 77

Dispersed guinea-pig adrenal cells have been employed in the in vitro estimation of the biological potency and sites of action of drugs acting against the adrenal. The effect of 12 drugs on cortisol secretion from cells stimulated with adrenocorticotrophin (ACTH, 50 ng/L, a 95% saturating dose) has been tested. All the drugs depressed cortisol output in a dose-related fashion. The concentration of drug which inhibited secretion by 50% was (mumol/L, mean +/- SEM): etomidate 0.1 +/- 0.002; epostane 0.44 +/- 0.02: 17-ketotrilostane 0.55 +/- 0.04: trilostane 1.3 +/- 0.1: metyrapone 3.5 +/- 0.6: cyproterone acetate 4.6 +/- 0.2: megestrol acetate 11 +/- 2: danazol 22 +/- 2: aminoglutethimide 41 +/- 5: stanozolol 50 +/- 4: thiopentone 160 +/- 18: propofol 170 +/- 18. The sites of the anti-steroidogenic effect of seven of these drugs have also been established using a method based upon the sequential stimulation by the exogenous precursor steroids of the various steps leading to the biosynthesis of cortisol by adrenal cells. Propofol acts between ACTH binding and pregnenolone production, trilostane, megestrol acetate and cyproterone acetate are 3 beta-hydroxysteroid dehydrogenase inhibitors whereas metyrapone, etomidate and thiopentone act at 11 beta-hydroxylase.
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PMID:On the assessment of the in vitro biopotency and site(s) of action of drugs affecting adrenal steroidogenesis. 302 52

Ketoconazole, an orally-active, broad spectrum mycotic agent, was shown to inhibit in vitro human placental microsomal aromatase but was without effect on 3 beta-hydroxysteroid dehydrogenase-isomerase (3 beta-HSD-I) and 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) activities. The Km of placental aromatase for testosterone was 30 +/- 1.1 nmol/l (mean +/- SEM, n = 6). Inhibition (determined by Lineweaver-Burk plot) was non-competitive with respect to substrate with a Ki value of 3.0 +/- 1.4 mumol/l (mean +/- SEM, n = 6). Ketoconazole was without effect on the 3 beta-HSD-I and 17 beta-HSD activities when using [3H] pregnenolone and [3H] oestradiol, respectively, as substrates. Since ketoconazole is known to inhibit cytochrome P-450-dependent enzyme reactions, the results of the present study support the contention that cytochrome P-450 is involved in the aromatisation process.
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PMID:Effect of ketoconazole on placental aromatase, 3 beta-hydroxysteroid dehydrogenase-isomerase and 17 beta-hydroxysteroid dehydrogenase. 302 21

Stereological analysis of Leydig cell and macrophage volume density along the long axis of the guinea pig testis was assessed quantitatively by histometric point counting. Morphological identification of Leydig cells was accomplished by staining for 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), whereas macrophages were identified by vital staining (trypan blue). The average percentage of Leydig cell density constitutes about 10.17 +/- 0.23% at the cranial level (level 1) and about 8.8 +/- 0.21% at the caudal level (level 4). Leydig cell density through four testicular levels showed no significant difference among levels 1, 2, and 3, whereas level 4 was significantly different. The percentage of macrophage density, on the other hand, was approximately 0.4% +/- SEM per cross-sectional profile. It may thus be concluded that the macrophage density within the guinea pig testis does not bias histometric studies of the Leydig cell population to any significant degree, but that regional differences in Leydig cell volume density could influence validity of sampling if tissue procurement is from different testicular levels in successive experiments.
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PMID:Stereological study of Leydig cell density in the guinea pig testis. 378 73

It is well recognized that in the fetal adrenal cortex, 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) activity is lower and in fetal tissues, steroid sulfokinase (SK) is higher than in the adult. In order to clarify a part of the development processes of the adrenal cortex or steroidgenesis in humans, a combined radioimmunoassay (RIA) method to estimate serum 17 alpha-hydroxypregnenolone (17-OH-delta 5 P), 17 alpha-hydroxypregnenolone sulfate (17-OH-delta 5 P-S) and 17 alpha-hydroxyprogesterone (17-OH-delta 4P) was devised. The method consisted of the following procedures: 1) diethyl ether extraction and chromatographic separation of unconjugated steroids (17-OH-delta 5P and 17-OH-delta 4P), 2) enzymatic hydrolysis of 17-OH-delta 5P-S using the residue of diethyl ether extraction for a material, 3) diethyl ether extraction and chromatographic purification of hydrolyzed 17-OH-delta 5P-S, and 4) RIAs for 17-OH-delta 5-P to estimate 17-OH-delta 5P and 17-OH-delta 5P-S concentration, and for 17-OH-delta 4P. Extracted 17-OH-delta 5P was well separated from 17-OH-delta 4P by Sephadex LH-20 microcolumn chromatography, using a benzene/methanol = 95/5 (v/v) solvent as a mobile phase. Several procedures for hydrolysis or solvolysis of 17-OH-delta 5P-S were compared using available tritiated delta 5-3 beta-hydroxysteroids including dehydroepiandrosterone (DHA), DHA sulfate (DHA-S) and 17-OH-delta 5P, and it was found that the most suitable method was an enzymatic hydrolysis by arylsulfatase from Helix Pomatia in an appropriate condition in which the percent hydrolysis was 92.9 +/- 1.2 (mean +/- SEM)%. The final percent recoveries were 88.7 +/- 1.2% in 17-OH-delta 4P, 90.7 +/- 1.4% in 17-OH-delta 5P and 78.1 +/- 2.1% in 17-OH-delta 5P-S, respectively. A suitable antiserum and its final dilution titer for RIA of 17-OH-delta 5P (hydrolyzed 17-OH-delta 5P-S also) was 1:12,000 dilution of anti-17-OH-delta 5P-3-succinate-BSA serum. An anti-7-oxo-17-OH-delta 5P-7-carboxymethyloxime-BSA serum was considered to be unsuitable for the measurement of hydrolyzed 17-OH-delta 5-P-S, presumably because of a significant cross-reactivity with a large amount of unknown steroid sulfates simultaneously hydrolyzed.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[A combined radioimmunoassay method for the determination of 17 alpha-hydroxypregnenolone, 17 alpha-hydroxypregnenolone sulfate and 17 alpha-hydroxyprogesterone in human blood]. 405 6

The luteinizing hormone releasing hormone analog D-Trp6-Pro9-Net-LHRH (LHRHa) inhibits rat testicular testosterone secretion. To determine whether LHRHa decreases serum testosterone concentrations solely by inhibiting gonadotropin secretion or, in addition, by influencing directly testicular testosterone biosynthesis, we examined the effects of LHRHa on the activities of 5 key testicular steroidogenic enzymes. Thirty hypophysectomized, hOG treated rats were given either LHRHa (1 micrograms sc/day) or saline during 7 days. The LHRHa treated animals exhibited a significant decrease of serum testosterone when compared to the control group (498 +/- 37 ng/dl vs 2044 +/- 105 ng/dl, mean +/- SEM, P less than 0.001). 17-Hydroxyprogesterone serum levels were also decreased in the LHRHa treated rats (61 +/- 6 ng/dl vs 93 +/- 7 ng/dl, P less than 0.005), while serum progesterone levels were similar in both groups of animals. These changes in steroid concentrations were associated with decreases in the microsomal enzyme activities of 17-hydroxylase (37 +/- 9 vs 654 +/- 41 pmol/mg protein/min, P less than 0.001), 17,20-desmolase (103 +/- 9 vs 522 +/- 47 pmol/mg protein/min, P less than 0.001), 3 beta-hydroxysteroid dehydrogenase (1.7 +/- 0.02 vs 4.1 +/- 0.1 nmol/mg protein/min, P less than 0.001), aromatase (95 +/- 7 vs 228 +/- 6 pmol/mg protein/min, P less than 0.001) and 17-ketosteroid reductase (167 +/- 9 vs 290 +/- 18 pmol/mg protein/min, P less than 0.01) in the LHRHa treated animals. These findings indicate that LHRHa can inhibit directly rat testicular testosterone biosynthesis.
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PMID:Direct effect of the luteinizing hormone releasing hormone analog D-Trp6-Pro9-Net-LHRH on rat testicular steroidogenesis. 639 51


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