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  • 1
    Publication Date: 2017-01-07
    Description: Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 143 (2006): 397-403, doi:10.1016/j.cbpb.2005.12.017.
    Description: Steroid metabolism studies have yielded evidence of 17β-hydroxysteroid dehydrogenase (17β-HSD) activity in corals. This project was undertaken to clarify whether there are multiple isoforms of 17β-HSD, whether activity levels vary seasonally, and if zooxanthellae contribute to activity. 17β-HSD activity was characterized in zooxanthellate and azooxanthellate coral fragments collected in summer and winter and in zooxanthellae cultured from M. capitata. More specifically, 17β-HSD activity was characterized with regard to steroid substrate and inhibitor specificity, coenzyme specificity, and Michaelis constants for estradiol (E2) and NADP+. Six samples each of M. capitata and T. coccinea (three summer, three winter) were assayed with E2 and NADP+. Specific activity levels (pmol/mg protein) varied 10-fold among M. capitata samples and 6-fold among T. coccinea samples. There was overlap of activity levels between summer and winter samples. NADP+/NAD+ activity ratios varied from 1.6 to 22.2 for M. capatita, 2.3 to 3.8 for T. coccinea and 0.7 to 1.1 for zooxanthellae. Coumestrol was the most inhibitory of the steroids and phytoestrogens tested. Our data confirm that corals and zooxanthellae contain 17β-HSD and are consistent with the presence of more than one isoform of the enzyme.
    Description: Support for this work was provided by the EPA STAR fellowship program and the University of Hawaii Sea Grant College Program.
    Keywords: 17β-hydroxysteroid dehydrogenase ; Steroid ; Coral ; Invertebrate ; Zooxanthellae ; Phytoestrogens ; Estradiol ; Scleractinia
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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  • 2
    Publication Date: 2022-05-25
    Description: Author Posting. © Elsevier B.V., 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Molecular and Cellular Endocrinology 301 (2009): 27-36, doi:10.1016/j.mce.2008.09.037.
    Description: Cnidarians occupy a key evolutionary position as a sister group to bilaterian animals. While cnidarians contain a diverse complement of steroids, sterols, and other lipid metabolites, relatively little is known of the endogenous steroid metabolism or function in cnidarian tissues. Incubations of cnidarian tissues with steroid substrates have indicated the presence of steroid metabolizing enzymes, particularly enzymes with 17β-hydroxysteroid dehydrogenase (17β-HSD) activity. Through analysis of the genome of the starlet sea anemone, Nematostella vectensis, we identified a suite of genes in the short chain dehydrogenase/reductase (SDR) superfamily including homologs of genes that metabolize steroids in other animals. A more detailed analysis of Hsd17b4 revealed complex evolutionary relationships, apparent intron loss in several taxa, and predominantly adult expression in N. vectensis. Due to its ease of culture and available molecular tools N. vectensis is an excellent model for investigation of cnidarian steroid metabolism and gene function.
    Description: We are grateful for financial support from the Woods Hole Oceanographic Institution (WHOI) for Assistant Scientist Endowed Support Funds (AMT), the WHOI Academic Programs Office and the Beacon Institute for Rivers and Estuaries (AMR).
    Keywords: Evolution ; Hydroxysteroid dehydrogenase ; Short chain dehydrogenase/reductase
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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  • 3
    ISSN: 0730-2312
    Keywords: gynecologic tumor cells ; cancer cells ; steroids ; steroid metabolism ; hydroxysteroid dehydrogenase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Although there is a growing body of evidence that 17β-hydroxysteroid oxidoteductase plays a role the regulation of steroid levels in epithelial tumors of the endometrium and breast, out knowledge of its role in other gynecologic tumors is limited. In this investigation, the 17β-hydroxysteroid oxidoreductase activity of cell lines derived from two ovarian tumors (OVCAR-3, CAOV-3) and an epidermoid tumor of the vulva (A431) was assayed under conditions which differentiate between 17β-hydroxysteriod oxidoreductase type 1, a cytosolic isoform highly specific for estradiol, and type 2, a membrane bound isoform reactive with both estradiol and testosterone. On the basic of estradiol/testosterone activity ratios, all three cell lines appear to have type 2-like activity, with the specific activity of A431 markedly greater than that of the other cell lines. Estradiol, progesterone, or EGE, alone or in combination, were without effect on the enzymatic activity of OVCAR-3 cells. EGE decreased the activity of CAOV-3 cells slightly. In contrast, EGE stimulated A431 17β-hydroxysteriod oxidoreductase activity 7-8-fold over a 5-day exposure. Estradiol or progesterone, singly or in combination, also did not effect the enzymatic activity of A431 cells. However, progesterone inhibited the increase in activity seen in the presence of EGE. With EGE, estradiol, and progesterone together, the increase in enzymatic activity was comparable to that with EGE alone. The effects of estradiol and progesterone appear to result from steroid actions following binding of EGE to low-affinity receptors on A431 cells. © 1995 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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