Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.1.1.3 (HSD)
3,464 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The placenta is the primary source of estrogens and progesterone during pregnancy. Because pregnant diabetic women are reported to have lower serum estrogen and higher progesterone levels than nondiabetic pregnant women, and placental insulin-like growth factor II (IGF-II) production may be elevated during diabetic pregnancy, the role of IGF-II in the regulation of human cytotrophoblastic aromatase, 3 beta-hydroxysteroid dehydrogenase (3 beta HSD), and P450 cholesterol side-chain cleavage (P450scc) enzyme activities was studied. Incubation of cytotrophoblasts with IGF-II for 24 h significantly diminished the ability of these cells to convert androstenedione to estrogens by 92.3 +/- 6.6 (SE)%. IGF-II could suppress aromatase activity at a concentration as low as 2.0 ng/ml. Preincubation of cells with either insulin, IGF-I, or a monoclonal anti-IGF-I receptor antibody did not alter IGF-II's potent inhibitory effect. Treatment with mannose 6-phosphate alone also resulted in significant suppression of aromatase activity, and concurrent treatment with both mannose 6-phosphate and IGF-II resulted in greater inhibition than with either agent alone. These observations suggest that IGF-II suppresses aromatase activity by activation of its own specific receptor. In contrast, incubation of cytotrophoblasts with IGF-II for 24 h significantly increased the 3 beta HSD activity (as determined by the conversion of pregnenolone to progesterone) and P450scc activity (as determined by the conversion of 25-hydroxycholesterol to progesterone) of these cells. IGF-II's ability to stimulate these enzymatic processes was found to be comparable in magnitude to that of IGF-I. IGF-II-stimulated 3 beta HSD activity was completely inhibited by concurrent treatment with either actinomycin D or cycloheximide, suggesting that new mRNA and protein synthesis are required for IGF-II to exert its stimulatory effect. These studies indicate that IGF-II is a potent inhibitor of human cytotrophoblastic aromatase activity in vitro. In addition, IGF-II can stimulate cytotrophoblastic 3 beta HSD and P450scc activities. Since placental IGF-II production in pregnant diabetic women may be augmented, these observations may help explain the lower serum estrogen and higher progesterone levels associated with pregnancy in the diabetic patient.
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PMID:Insulin-like growth factor II is a potent inhibitor of the aromatase activity of human placental cytotrophoblasts. 222

The development of long term culture conditions with which to study the regulation of expression of aromatase, cholesterol side-chain cleavage enzyme, and 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) in human granulosa-lutein cells is described in this report. Conditions have been established for the dispersal, growth, freezing, and storage of functional human granulosa cells isolated from preovulatory follicles of women undergoing laparoscopy for gamete intrafallopian tube transfer and in vitro fertilization procedures. Optimal growth conditions for human granulosa-lutein cells were determined by plating cells at a low density and testing the capacity of a variety of culture conditions to support growth. A combination of fetal bovine serum (FBS), horse serum, and the serum substitute UltroSer G was found to increase cell number to maximal levels, 8- to 10-fold higher than with sera alone. Human granulosa-lutein cells grown under these conditions had a doubling rate of 36-40 h and were morphologically distinct from human theca interna cells grown under similar conditions. Human granulosa-lutein cells treated with forskolin retracted and rounded up, whereas cultures of human ovarian theca interna cells or human fibroblasts treated similarly did not retract. Human granulosa-lutein cells were grown for successive passages and transferred to serum-free medium containing forskolin, LH, hCG, or cholera toxin. Addition of these agents resulted in a time- and dose-dependent increase in aromatase activity and progesterone secretion. In these studies FSH treatment was found not to increase aromatase activity. In a study of the time course of 3 beta HSD activity in the absence of forskolin under serum-free conditions, it was found that 3 beta HSD activity increased 3-fold during the 72-h treatment period. Forskolin-stimulated 3 beta HSD activity also increased in a time-dependent manner, with levels in treated cells 3-fold higher than those in control cells. Northern analysis performed on total RNA obtained from forskolin- or hCG-stimulated granulosa-lutein cells confirmed that the increase in aromatase activity was associated with a corresponding increase in levels of mRNA specific for aromatase cytochrome P-450. Levels of mRNA encoding cholesterol side-chain cleavage cytochrome P-450 were similarly increased in cells treated with forskolin compared with unstimulated values at each of the time points investigated. Under serum-free conditions in the absence of stimulation, the 3.4-kilobase band of aromatase cytochrome P-450 mRNA was detectable.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Proliferating human granulosa-lutein cells in long term monolayer culture: expression of aromatase, cholesterol side-chain cleavage, and 3 beta-hydroxysteroid dehydrogenase. 237 Feb 96

The well-known hormone dependency of the normal human prostate and of BPH and prostatic carcinoma stimulated the study of cellular events which would possibly lead to specific steroid hormone patterns under the respective prevailing condition. In extending earlier observations on a significant DHT and E2 accumulation especially in stromal nuclei of BPH recent data on the uptake and metabolism of adrenal androgens clearly underline the important differential role of either stromal or epithelial cells. Epithelium and stroma of BPH contained a quantitatively different pattern of steroid metabolizing enzymes. This dualism of enzyme activity favours the conversion of testosterone to DHT in the stroma while androgens of adrenal origin are metabolized mainly in BPH epithelium. Further to quantitative data on the intracellular distribution of the three sex steroid classes (estrogens, androgens, adrenal androgens) and to Km and Vmax values of the respective steroid metabolizing enzymes in question (5 alpha-reductase, 3 alpha/beta-HSDH, 17 beta-HSDH, sulfatase, aromatase) the impact of antihormones (cyproterone acetate) on the intratissular distribution and on the in vivo cytosolic and nuclear binding of DHT as well as on its biological implications will be discussed. The data present a complicated picture, which points to special roles of epithelial and stromal cells and allow speculations on the relative importance of testicular and adrenal androgens and estrogens for the development and maintenance of both normal and diseased human prostates. Furthermore, the determination of intratissular steroid concentrations can be an important tool to understand and to ground a rational basis for a hormonal treatment of prostatic tumors.
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PMID:Intratissular androgens in benign prostatic hyperplasia and prostatic cancer. 243 5

As an extension of our studies on androgen metabolism in epithelium and stroma of human benign prostatic hyperplasia (BPH) tissue our attempts to demonstrate the presence of aromatase are described. Additionally, the question is raised whether the aromatase inhibitor 17 alpha-oxa-D-homoandrosta-1.4-diene-3.17-dione (testolactone) might also act by inhibition of 17 beta-hydroxysteroid dehydrogenase (17 beta-HSDH). In vitro metabolism and inhibition were analyzed by TLC. The main results were: (1) Two aromatase assays (estrone formation and tritium release) were tested with placenta microsomes. Identical results were obtained (Km = 43 +/- 7 nmol/l n = 5; Vmax = 100 resulted in recovery of the aromatase activity added. (3) In BPH tissue alone, formation of estrone from androstenedione could not be detected (less than 7 x 10(-17) mol/min per mg protein, n = 8). (4) 4-Hydroxyandrostenedione inhibited placental aromatase (Ki = 37 nmol/l) distinctly better than 17 beta-HSDH from human BPH (Ki = 18 mumol/l), whereas the Ki values for testolactone (3.7 and 29 mumol/l, respectively) were more similar. It is concluded that aromatization of androgens is not an important pathway in BPH tissue. An alternative mode of action of testolactone by inhibition of 17 beta-HSDH is discussed.
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PMID:Metabolism of androgens in human benign prostatic hyperplasia: aromatase and its inhibition. 244 91

GnRH agonist and synthetic steroid such as Danazol, Medroxyprogesterone acetate (MPA) and Gestrinone are useful for the treatment of patients with endometriosis. These compounds induce atrophy and regression of endometriotic tissue, but the action mechanisms are still unclear. The present study, therefore, was undertaken to elucidate the mechanisms of these compounds in the treatment of endometriosis. In addition, a combination therapy with these compounds for endometriosis was also evaluated with an experimental animal model. Effects of GnRH agonist, Danazol and GnRH/Danazol combination on experimental endometriosis were evaluated in female rats. Endometrium autotransplanted under the renal capsule markedly decreased in size following castration. Histologic examination indicated atrophy and regression of the endometrial explant. The changes of endometrial explant were also induced by GnRH agonist, Danazol and combination treatment. However, a combination therapy with GnRH agonist and Danazol (93%) was shown to be superior to GnRH agonist (65%) and Danazol alone (45%) to induce atrophy and regression of experimental endometriosis. As expected, GnRH agonist significantly decreased serum E2, but Danazol did not at all. It is suggested that a combination therapy with GnRH agonist and Danazol may be a potential modality in the treatment of endometriosis. In order to evaluate whether Danazol, MPA, and Gestrinone has a direct inhibitory effect to synthesize estrogen, immature female rats were hypophysectomized and the ovaries were stimulated by a daily PMS injection. Administration of Danazol to the rats for two weeks stimulated the synthesis of 17, 20-lyase, 17 beta-HSD and aromatase activity, but did not inhibit any enzyme activities.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Studies on endocrine therapy of endometriosis]. 253 Feb 91

Steroidogenic enzyme activities in the left ovary and the testes of 9- to 15-day-old chicken embryos were measured, and development of the activities was compared between sexes. Activity of delta 5-3 beta-hydroxysteroid dehydrogenase coupled with delta 5-delta 4 isomerase in the ovary and in the testis was comparable, and did not change throughout the period examined. Activity of 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) in the ovary was similar to or higher than that in the testis, depending on substrates employed. In both gonads, 17 beta-HSD activity did not change or tended to decrease from 9 to 15 days of development. On the other hand, activities of 17 alpha-hydroxylase, C-17--C-20 lyase in the ovary were three to eight times those in the testis, and aromatase activity in the ovary was definitely higher than that in the testis at all stages examined. The activities of 17 alpha-hydroxylase, C-17--C-20 lyase, and aromatase significantly increased from 9 to 11 days only in the ovary. From 13 to 15 days, the activities of 17 alpha-hydroxylase and C-17--C-20 lyase markedly increased only in the testis. These results suggest that, in the gonads of developing chicken embryos, there are sexual differences in the regulation of 17 alpha-hydroxylase, C-17--C-20 lyase, and aromatase activities.
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PMID:Developmental changes of steroidogenic enzyme activities in the embryonic gonads of the chicken: the sexual difference. 284 54

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

Changes in amago salmon (Oncorhynchus rhodurus) ovarian thecal and granulosa layer function in association with the production of two biologically important ovarian mediators of oocyte growth and maturation in salmonids, estradiol-17 beta and 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-diOHprog), were investigated using isolated follicular preparations in vitro. A distinct shift of steroidogenic responses of intact follicles from estradiol-17 beta to 17 alpha,20 beta-diOHprog in response to partially purified chum salmon gonadotropin (SGA) occurred immediately prior to oocyte maturation. Aromatase activity in granulosa layers increased during vitellogenesis and decreased rapidly prior to oocyte maturation. This decrease in aromatase activity was coincident with the decreased ability of intact follicles to produce estradiol-17 beta in response to SGA. Since testosterone production in thecal layers did not decline during this time, the reduced production of estradiol-17 beta by postvitellogenic follicles is due, in part, to decreased aromatase activity in granulosa layers. Immediately prior to oocyte maturation, intact follicles acquire an increased ability to produce 17 alpha,20 beta-diOHprog in response to SGA. Although granulosa layers first acquired the ability to convert exogenous 17 alpha-hydroxyprogesterone (17 alpha-OHprog) to 17 alpha,20 beta-diOHprog (20 beta-hydroxysteroid dehydrogenase, 20 beta-HSD, activity) in response to SGA about 2 months prior to oocyte maturation, thecal layers did not develop the ability to produce 17 alpha-OHprog in response to SGA until immediately prior to oocyte maturation. Thus, changes in thecal cell function are critical for intact follicles to acquire the ability to produce 17 alpha,20 beta-diOHprog in response to gonadotropin.
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PMID:Developmental changes in steroidogenic responses of ovarian follicles of amago salmon (Oncorhynchus rhodurus) to chum salmon gonadotropin during oogenesis. 318 35

Changes in the capacity of medaka, Oryzias latipes, ovarian follicles to convert exogenous 17 alpha-hydroxyprogesterone (17 alpha-OHprog) or testosterone to testosterone, estradiol-17 beta, and 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-diOHprog) were examined using 18-hr incubations. Under a constant long photoperiod (14 hr light-10 hr dark) at 26 degrees medaka spawn daily within 1 hr of the onset of light. Under these conditions, vitellogenesis and oocyte maturation of individual follicles occur within 72 hr, allowing accurate determination of the time of oocyte maturation and ovulation. In the absence of substrates, vitellogenic follicles isolated between 28 and 16 hr before spawning produced increased amounts of estradiol-17 beta, while postvitellogenic follicles between 14 and 8 hr produced a large amount of 17 alpha,20 beta-diOHprog. However, under the same conditions, testosterone levels were very low in follicles from all stages of development. The capacity of follicles to produce estradiol-17 beta in response to 17 alpha-OHprog or testosterone increased as follicles developed from the early to late vitellogenic stage, but declined during oocyte maturation. Maximum estradiol-17 beta production was observed in follicles at 20 hr before spawning. In contrast, the conversion of 17 alpha-OHprog to 17 alpha,20 beta-diOHprog was low in vitellogenic follicles and increased in follicles isolated immediately prior to or during oocyte maturation, with maximum 17 alpha,20 beta-diOHprog production occurring in follicles isolated at 14 hr before spawning. These results demonstrate a distinct shift in the activities of steroidogenic enzymes from C17-20 lyase, 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD), and aromatase to 20 beta-hydroxysteroid dehydrogenase (20 beta-HSD) occurring in the medaka ovarian follicles immediately prior to oocyte maturation.
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PMID:Influence of follicular development on steroid production in the medaka (Oryzias latipes) ovarian follicle in response to exogenous substrates. 319 72

Recently, a protein fraction [follicle regulatory protein (FRP)] which inhibits FSH-induced granulosa cell aromatase activity was isolated from both human and porcine follicular fluid. In this study, the actions of FRP on 3 beta-hydroxysteroid dehydrogenase (3 beta-HSDH) activity were examined using granulosa cells obtained from hyperstimulated patients undergoing oocyte aspiration for in vitro fertilization. Granulosa cells were cultured with 0, 167, or 500 micrograms/ml FRP with or without human menopausal gonadotropin (hMG; 10 mIU/ml). After 48 h, the medium (S) was removed and stored. Cells then were mechanically lysed and centrifuged at 10,000 X g. The supernatant was further centrifuged (100,000 X g) to obtain a microsomal fraction (M) and cytosol (C). The M fraction was resuspended in medium 199 with 10(-6) M pregnenolone plus 5 microM NAD+ and incubated for 2 h to determine 3 beta-o1 dehydrogenase activity. The S, C, and M fractions were all assayed for progesterone (P) by RIA. hMG markedly increased P concentrations in the S and C fractions. The M fraction demonstrated a hMG-dependent enhancement in 3 beta-HSDH activity. However, the hMG-associated S, C, and M P levels were decreased in granulosa cells coincubated with FRP. In conclusion, ovarian steroidogenesis may be dependent on the integrated interactions of both gonadotropins and local nonsteroidal paracrine/autocrine modulators of granulosa cell function.
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PMID:Effect of human menopausal gonadotropin and follicle regulatory protein(s) on 3 beta-hydroxysteroid dehydrogenase in human granulosa cells. 392 17


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