Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q7LGC8 (HSD)
 3,196 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The capability of granulosa and theca interna cells, from preovulatory follicles of the domestic hen, to metabolize steroid precursors was evaluated. Granulosa and theca interna cells were isolated from ovarian preovulatory follicles at three different developmental stages: F1, F3 and F5. Tritiated pregnenolone (P5), progesterone (P4), dehydroepiandrosterone (DHEA), androstenedione (A4) and testosterone (T) were employed as precursors and their metabolic products were evaluated. The major metabolite of P5 by granulosa cells was P4, but we also observed low amounts of 5beta-pregnandione. DHEA metabolism by granulosa cells yielded mainly A4, and minute quantities of 5beta-androstan-3,17-dione (5beta-dione) were detected. The only significant metabolite obtained in granulosa cells from A4 was 5beta-dione, whereas T was only transformed into A4. On the other hand, P5 metabolism by theca interna cells yielded A4 as the main product, also P4, 17alpha-OHP4, 17alpha-OHP5, 5beta-pregnandione, and DHEA, were found. When DHEA was the precursor A4 was produced in higher amounts than 5beta-dione. A4 was mainly transformed into 5beta-dione. In similar conditions, T was transformed into A4. These results show that granulosa cells have enzymatic activities of 3beta-hydroxysteroid dehydrogenase/5-4 isomerase (3beta-HSD from P5 and DHEA), 17beta-hydroxysteroid dehydrogenase (17beta-HSD from T) and 5beta-reductase (from P5, DHEA and A4). Whereas theca interna cells have enzymatic activities of cytochrome P450c17 (from P5 and P4), 3beta-HSD (from P5 and DHEA), 17beta-HSD (from T) and 5beta-reductase (from P4, DHEA and A4). These data support the concept that theca interna cells have the ability to synthesize androgens from progestins produced in granulosa cells. In addition, since theca interna cells did not show the capacity to aromatize androgens suggests that interaction between theca interna and theca externa cells occurs in vivo, thus confirming the three cell model for estrogen production. Furthermore, the fact that other metabolites were produced both in granulosa and theca interna cells, but in a different extent, suggests that complex mechanisms are participating in the regulation of steroid synthesis in avian ovary follicles.
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PMID:Steroid metabolism in granulosa and theca interna cells from preovulatory follicles of domestic hen (Gallus domesticus). 972 17

Neurosteroids are now known to be synthesized de novo in the nervous system through mechanisms at least partly independent of peripheral steroidogenic glands. In mammals, the presence of the cholesterol side-chain cleavage enzyme (cytochrome P450scc) and the enzyme 3beta-hydroxysteroid dehydrogenase/Delta5-Delta4-isomerase (3beta-HSD) has been well established in the brain, whereas limited information has been available on the enzyme 17alpha-hydroxylase/c17, 20-lyase (cytochrome P450c17), which converts pregnenolone to dehydroepiandrosterone, one of the most abundant neurosteroids. In addition, little is known regarding developmental changes in these steroidogenic enzymes during postnatal life. Thus, the pathway of neurosteroid formation in the brain is still incomplete. Therefore, we examined expressions of the messenger RNAs (mRNAs) encoding for three key enzymes, P450scc, P450c17 and 3beta-HSD, in the rat brain at different postnatal ages using RT-PCR analysis. The expression of P450scc mRNA was found throughout the brain at the same level, while the 3beta-HSD mRNA expression was higher in the cerebellum and cerebrum than in other brain regions. The P450c17 mRNA was highly expressed in the mesencephalon. On the other hand, higher expressions of the cerebellar and cerebral 3beta-HSD mRNAs were observed only in neonatal life. In contrast, the expression of P450scc mRNA was relatively constant during neonatal life and in adulthood. A similar constant expression of the P450c17 mRNA was evident in the mesencephalon. Serial Southern hybridization in this study confirmed the specific mRNA expression corresponding to each enzyme. These results suggest that in the postnatal rat the expression of 3beta-HSD or P450c17 mRNA may be age- or region-dependent, unlike the P450scc mRNA expression.
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PMID:Age- and region-specific expressions of the messenger RNAs encoding for steroidogenic enzymes p450scc, P450c17 and 3beta-HSD in the postnatal rat brain. 972 6

3beta-hydroxysteroid dehydrogenase/steroid delta5-->4-isomerase (3beta-HSD/isomerase) was expressed by baculovirus in Spodoptera fungiperda (Sf9) insect cells from cDNA sequences encoding human wild-type I (placental) and the human type I mutants - H261R, Y253F and Y253,254F. Western blots of SDS-polyacrylamide gels showed that the baculovirus-infected Sf9 cells expressed the immunoreactive wild-type, H261R, Y253F or Y253,254F protein that co-migrated with purified placental 3beta-HSD/isomerase (monomeric Mr=42,000 Da). The wild-type, H261R and Y253F enzymes were each purified as a single, homogeneous protein from a suspension of the Sf9 cells (5.01). In kinetic studies with purified enzyme, the H261R mutant enzyme had no 3beta-HSD activity, whereas the Km and Vmax values of the isomerase substrate were similar to the values obtained with the wild-type and native enzymes. The Vmax (88 nmol/min/mg) for the conversion of 5-androstene-3,17-dione to androstenedione by the Y253F isomerase activity was 7.0-fold less than the mean Vmax (620 nmol/min/mg) measured for the isomerase activity of the wild-type and native placental enzymes. In microsomal preparations, isomerase activity was completely abolished in the Y253,254F mutant enzyme, but Y253,254F had 45% of the 3beta-HSD activity of the wild-type enzyme. In contrast, the purified Y253F, wild-type and native enzymes had similar Vmax values for substrate oxidation by the 3beta-HSD activity. The 3beta-HSD activities of the Y253F, Y253,254F and wild-type enzymes reduced NAD+ with similar kinetic values. Although NADH activated the isomerase activities of the H261R and wild-type enzymes with similar kinetics, the activation of the isomerase activity of H261R by NAD+ was dramatically decreased. Based on these kinetic measurements, His261 appears to be a critical amino acid residue for the 3beta-HSD activity, and Tyr253 or Tyr254 participates in the isomerase activity of human type I (placental) enzyme.
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PMID:Site-directed mutagenesis identifies amino acid residues associated with the dehydrogenase and isomerase activities of human type I (placental) 3beta-hydroxysteroid dehydrogenase/isomerase. 974 38

The molecular mechanisms involved in luteolysis are still unclear in the primate. This study aimed to investigate the effect of induced luteolysis on the ovarian luteinizing hormone (LH) receptor and the steroidogenic enzyme, 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in the marmoset monkey. Luteolysis was induced in the mid-luteal phase either directly by systemic prostaglandin F2alpha (PGF2alpha), or indirectly by LH withdrawal using systemic gonadotrophin releasing hormone antagonist (GnRHant) treatment. The LH receptor was studied by isotopic mRNA in-situ hybridization and in-situ ligand binding and 3beta-HSD expression was studied using isotopic mRNA in-situ hybridization and immunohistochemistry. Induced luteolysis was associated with a reduction in the expression of LH receptor (P < 0.0001) and 3beta-HSD mRNA, closely followed by a reduction in the LH receptor (P < 0.05) and 3beta-HSD protein concentrations within 24 h. There were no differences in the findings whether luteolysis was induced with PGF2alpha or GnRHant. This study shows that disparate mechanisms to induce luteolysis in the primate result in an identical rapid loss of the LH receptor and 3beta-HSD. In conclusion, induced luteolysis leads to rapid loss of the steroidogenic pathway in luteal cells.
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PMID:Induced luteolysis in the primate: rapid loss of luteinizing hormone receptors. 980 79

Troglitazone (a thiazolidinedione that improves insulin resistance) lowers elevated androgen concentrations in women with polycystic ovarian syndrome. In this study, we assessed the direct effects of troglitazone on steroidogenesis in porcine granulosa cells. Troglitazone inhibited progesterone production in a dose- and time-dependent manner (earliest effects at 4 h, maximum at 24 h) without affecting cell viability. Progesterone production was also inhibited by troglitazone in the presence of 25-hydroxycholesterol, indicating that the drug does not affect intracellular cholesterol transport. Troglitazone also inhibited FSH- and forskolin-stimulated progesterone secretion. The reduced progesterone production was accompanied by marked elevations of pregnenolone concentrations, suggesting inhibition of 3beta-hydroxysteroid dehydrogenase (3beta-HSD). The activity of 3beta-HSD in troglitazone-treated granulosa cells was decreased by more than 60%, compared with controls after 24 h. Troglitazone did not affect aromatase activity in porcine granulosa cells. In summary, troglitazone has direct effects on porcine granulosa cell steroidogenesis. The drug specifically inhibits 3beta-HSD activity, resulting in impaired progesterone production. The clinical relevance of this direct in vitro effect on steroidogenesis needs further investigation.
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PMID:Troglitazone inhibits progesterone production in porcine granulosa cells. 983 34

The enzyme complex 3beta-hydroxysteroid dehydrogenase (3beta-HSD) is involved in the biosynthesis of all classes of active steroids. It is known that the enzymatic activity of 3beta-HSD is present not only in classical steroidogenic tissues, but also in many peripheral tissues including cardiac tissue. To determine whether 3beta-HSD is present in rat non-steroidogenic tissues, we examined cardiovascular tissues including the ventricle, atrium, aortic arch, abdominal aorta, and inferior vena cava by immunohistochemistry and Western blotting using polyclonal antibody raised against a synthetic peptide of human placental 3beta-HSD. By Western blotting, protein bands immunoreactive for anti-3beta-HSD were detected at molecular weights of 42 and 37 kDa in both the ventricle and atrium, whereas only a 37 kDa band was recognized in both the aortic arch and abdominal aorta. By immunohistochemistry, immunoreactivity for 3beta,-HSD was detected in both the ventricular and atrial cardiocytes, while immunostaining was also found, though faintly, in the smooth muscles of the aortic arch, abdominal aorta, and inferior vena cava. These results suggest that cardiocytes may synthesize the steroidogenic 3beta,-HSD enzyme.
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PMID:Immunohistochemical study of 3beta-hydroxysteroid dehydrogenase/delta5-delta4 isomerase in the rat cardiovascular system. 986 44

We have employed polyclonal antibodies to a peptide sequence of bovine steroidogenic acute regulatory (StAR) protein and human placental 3beta-hydroxysteroid dehydrogenase (3beta-HSD) to determine the localisation and distribution of these proteins in rat and bovine adrenal glands. Immunohistochemical staining demonstrated the presence of StAR protein in the zona glomerulosa (ZG), zona fasciculata (ZF), zona reticularis (ZR) and in the medulla of both species. For 3beta-HSD, immunostaining was observed in the ZG, ZF and ZR of the rat adrenal and was absent in the medulla. Immunoblotting experiments showed intense bands for StAR protein (30 kDa, 37 kDa) in the mitochondria of bovine ZG, ZF and medulla and a less intense band (30 kDa) in the microsomes. In rat ZG and ZF/R mitochondria only the 30 kDa protein was present. For 3beta-HSD, an intense band (42 kDa) was found in microsomes and mitochondria of rat and bovine ZG and ZFR. A very faint signal for 3beta-HSD was seen in adrenal medulla. In conclusion, StAR (or a closely related) protein is present throughout the adrenal gland in rat and bovine species in contrast to 3beta-HSD which is confined to the steroidogenic zones. The possible function of StAR protein in the adrenal medulla merits investigation.
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PMID:StAR protein is expressed in both medulla and cortex of the bovine and rat adrenal gland. 988 37

Sex steroids play a crucial role in the development and differentiation of normal mammary gland as well as in the regulation of breast cancer growth. Local intracrine formation of sex steroids from inactive precursors secreted by the adrenals, namely, dehydroepiandrosterone and its sulfate, may regulate growth and function of peripheral target tissues, including the breast. Both endocrine and paracrine influences on the proliferation of human breast cancer cells are well recognized. Breast tumors harbor tumor-associated macrophages and tumor-infiltrating lymphocytes that secrete a wide spectrum of cytokines. These factors may also contribute to neoplastic cell activity. The present study was designed to investigate the action of cytokines on 3beta-hydroxysteroid dehydrogenase (3beta-HSD) activity, which is an essential step in the biosynthesis of active estrogens and androgens in human breast cancer cell lines and in normal human mammary epithelial cells in primary culture. 3Beta-HSD activity was undetectable in ZR-75-1 and T-47D estrogen receptor-positive (ER)+ cells under basal growth conditions. This activity was markedly induced after exposure to picomolar concentrations of interleukin (IL)-4 or IL-13. The potent stimulatory effect of these cytokines on 3beta-HSD activity was also observed in the ER- MDA-MB-231 human breast cancer cell line and in normal human mammary epithelial cells (HMECs) in primary culture. The stimulation of 3beta-HSD activity by IL-4 and IL-13 results from a rapid increase in 3beta-HSD type 1 mRNA levels as measured by RT-PCR and Northern blot analyses. Such an induction of the 3beta-HSD activity may modulate androgenic and estrogenic biological responses as demonstrated using ZR-75-1 cells transfected with androgen- or estrogen-sensitive reporter constructs and treated with the adrenal steroid 5-androstene-3beta,17beta-diol. The DNA-binding activity of Stat6, a member of the signal transducers and activators of transcription gene family, is activated 30 min after exposure to IL-4 and IL-13 in human breast cancer cell lines as well as in HMECs in primary culture. In these cells, Stat6 activated by IL-4 or IL-13 binds to two regions of the 3beta-HSD type 1 gene promoter, containing Stat6 consensus sequences. IL-4 induction of 3beta-HSD mRNA and activity is sensitive to staurosporine. This protein kinase inhibitor also inhibits IL-4-induced Stat6 DNA-binding activity. Our data demonstrate for the first time that IL-4 and IL-13 induce 3beta-HSD type 1 gene expression, thus suggesting their involvement in the fine control of sex steroid biosynthesis from adrenal steroid precursors in normal and tumoral human mammary cells. Furthermore, aromatase and/or 5alpha-reductase(s) are expressed in the mammary gland and in a large proportion of human breast tumors. An increase in the formation of their substrates, namely, 4-androstenedione and testosterone, may well have a significant impact on the synthesis of active estrogens and androgens in these tissues.
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PMID:Induction of 3beta-hydroxysteroid dehydrogenase/delta5-delta4 isomerase type 1 gene transcription in human breast cancer cell lines and in normal mammary epithelial cells by interleukin-4 and interleukin-13. 989 13

Ovarian follicles were collected from perch belonging to the prespawning (vitellogenic) stage and incubated in vitro for 5 h in the absence (control) and presence of 3, 5, 3'-triiodothyronine (T3). Addition of increasing concentrations of T3 from 12.5 to 100 ng/ml caused a linear increase of 3beta-hydroxysteroid dehydrogenase/delta5-delta4-isomerase (3 beta-HSD) activity to 50 ng and then it leveled off indicating a saturation of enzyme activity with 50 ng T3. T3 stimulation of 3beta-HSD activity could be blocked by cycloheximide indicating the involvement of T3-induced protein (TIP) isolated and purified earlier from this laboratory. Addition of fish TIP purified from perch ovarian follicle (fTIP) or rat granulosa cell TIP to ovarian follicular incubation at a dose of 5 microg/ml significantly increased (P < 0.01) 3beta-HSD activity. To observe whether TIP acts directly on the enzyme or not, 3beta-HSD from perch ovarian follicle was purified to homogeneity by the following steps: (i) Sephadex G 75 gel filtration, (ii) DEAE-Sephacel chromatography, and (iii) NAD-affinity column chromatography. Purified 3beta-HSD gave a clear single band on an SDS gel and its molecular weight is 45 kDa. Addition of fTIP to an assay mixture containing purified 3beta-HSD resulted in a fourfold increase of the enzyme activity. fTIP alone did not show enzyme activity when incubated with the radiolabeled substrate. Addition of T3 (50 ng) to the 3beta-HSD assay mixture had no effect on the enzyme activity. Determination of Vmax and Km of the purified enzyme in the absence (control) and presence of fTIP demonstrated a considerable increase of 3beta-HSD affinity and rate of enzyme reaction.
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PMID:Thyroid hormone regulation of perch ovarian 3beta-hydroxysteroid dehydrogenase/delta5-delta4-isomerase activity: involvement of a 52-kDa protein. 1008 23

Recently, we have demonstrated, using biochemical and immunochemical methods, that the quail brain possesses the cholesterol side-chain cleavage enzyme (cytochrome P450scc) and produces pregnenolone and its sulfate ester. To clarify progesterone biosynthesis in the avian brain, therefore, we examined the expression of messenger RNA (mRNA) encoding for the enzyme 3beta-hydroxysteroid dehydrogenase/Delta5-Delta4-isomerase (3beta-HSD) and its enzymatic activity using the quail. RT-PCR analysis together with Southern hybridization indicated the expression of 3beta-HSD mRNA in the brain of sexually mature birds but with no clear-cut sex difference. Employing biochemical techniques combined with HPLC analysis, the conversion of pregnenolone to progesterone was found in brain slices of mature males. Progesterone biosynthesis was increased in a time dependent manner and completely abolished by trilostane, a specific inhibitor of 3beta-HSD. The enzymatic activity of 3beta-HSD was greatest in the cerebrum and lowest in the mesencephalon. A specific RIA indicated that progesterone concentrations in the different brain regions closely followed the level of 3beta-HSD activity. High levels of progesterone concentration were observed in the diencephalon and cerebrum with lowest values in the mesencephalon. Progesterone levels in the brain regions were significantly higher than those in the plasma. These results suggest that the avian brain possesses not only cytochrome P450scc but also 3beta-HSD and produces progesterone. It is also indicated that progesterone biosynthesis in the avian brain may be region-dependent.
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PMID:Expression and activity of 3beta-hydroxysteroid dehydrogenase/Delta5-Delta4-isomerase in different regions of the avian brain. 1008 43


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