Topic
Hydroxysteroid dehydrogenase
About: Hydroxysteroid dehydrogenase is a research topic. Over the lifetime, 1087 publications have been published within this topic receiving 28468 citations. The topic is also known as: hydroxysteroid dehydrogenase.
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TL;DR: The findings show that A549 cells express a pattern of steroid metabolism in which 17beta-HSD type 5 and 3alpha- HSD type 3 are the predominant enzymes, which has implications for the relative importance of testosterone and 5alpha-DHT in normal lung development and surfactant production.
Abstract: Surfactant synthesis within developing fetal lung type II cells is affected by testosterone and 5alpha-dihydrotestosterone (5alpha-DHT). The pulmonary epithelial cell line A549, isolated from a human lung carcinoma, like normal lung type II cell, produces disaturated phosphatidylcholines and has been widely used for studying the regulation of surfactant production. Androgen receptor has been detected in A549 cells; however, the capacity of these cells for androgen synthesis and metabolism has not been investigated at molecular level. This study was undertaken to identify the steroidogenic enzymes involved in the formation and metabolism of androgens from adrenal C19 steroid precursors in A549 cells. When cultured in the presence of normal FCS, A549 intact cells converted DHEA to androstenediol, androstenedione principally to testosterone, and 5alpha-DHT to 5alpha-androstane 3alpha,17beta-diol. High levels of 17beta-hydroxysteroid dehydrogenase (HSD) and 3alpha-HSD activities were detected in both cytosol and microsomes isolated from homogenates. Analysis of A549 RNA indicated the presence of 17beta-HSD type 4 and type 5, and of 3alpha-HSD type 3 messenger RNAs. Very low levels of 3beta-HSD type 1 and 5alpha-reductase type 1 messenger RNAs and activities were detected. With regard to active androgen formation, there was little or no capacity for the conversion of DHEA to 5alpha-DHT. In contrast, androstenedione was rapidly transformed to testosterone. The pattern of steroid metabolism was not affected by the use of charcoal-stripped FCS or by the synthetic glucocorticoid dexamethasone. Together, our findings show that A549 cells express a pattern of steroid metabolism in which 17beta-HSD type 5 and 3alpha-HSD type 3 are the predominant enzymes. The level of androgens is regulated at the level of catalysis in intact cells such that the intracellular level of testosterone is stabilized, whereas 5alpha-DHT is rapidly inactivated by reduction to 3alpha,17beta-diol. This pattern of androgen metabolism has implications for the relative importance of testosterone and 5alpha-DHT in normal lung development and surfactant production.
51 citations
TL;DR: Inhibition of 17β-HSD1 inhibitors from the hydroxyphenylnaphthol class by introduction of different heteroaromatic rings as well as substituted phenyl groups showed a good membrane permeation and metabolic stability and was orally available in the rat.
Abstract: Inhibition of 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1) is a novel and attractive approach to reduce the local levels of the active estrogen 17β-estradiol in patients with estrogen-depende...
51 citations
TL;DR: It is concluded that progestins induce 17‐HSD in T‐47D cells and that the induction occurs via an increased accumulation of enzyme protein.
Abstract: Steroid regulation of 17 beta-hydroxysteroid dehydrogenase (17-HSD) was studied in the T-47D human breast-cancer cell line, using a radioimmunoassay. In addition, 3 mRNA species (2.4, 1.4, and 0.9 kb) specific for the enzyme were shown to be present in these cells. All the synthetic progestins tested (ORG 2058, R5020, medroxyprogesterone acetate) significantly increased the immunoreactive enzyme protein concentration, while other types of steroids, such as testosterone, oestradiol and dexamethasone, were ineffective. The progestin-specific induction of 17-HSD was dose-related and was maximum in about 5 days. An antiprogestin, RU 486, when used in combination with synthetic progestins, blocked the progestin-induced increase of 17-HSD concentration very effectively. A good correlation was observed in the different experiments between the enzyme activity and the immunoreactive 17-HSD concentration. We conclude that progestins induce 17-HSD in T-47D cells and that the induction occurs via an increased accumulation of enzyme protein.
51 citations
TL;DR: The experimental results lead to the conclusion that mitochondrial 17β-HSD10 plays a significant part in a non-classical androgen synthesis pathway along with microsomal retinol dehydrogenases.
51 citations
TL;DR: Thin-layer chromatography of 14C-labeled bile acid products from reactions using cell-free extracts revealed a 3α-hydroxysteroid dehydrogenase activity for the BaiA1 protein, and results show thatThe BaiA proteins are novel 3α -Hydroxysteroids dehydrogenases.
Abstract: We have previously cloned and sequenced three members of a bile acid-inducible gene family from Eubacterium sp. strain VPI 12708 that encode 27,000-Mr polypeptides. Two copies of these genes (baiA1 and baiA3) are identical, while the third copy (baiA2) encodes a polypeptide sharing 92% amino acid identity with the baiA1 and baiA3 gene products. We have overexpressed the baiA1 gene in Escherichia coli and analyzed the expressed activity. Thin-layer chromatography of 14C-labeled bile acid products from reactions using cell-free extracts revealed a 3α-hydroxysteroid dehydrogenase activity for the BaiA1 protein. The BaiA1 protein could utilize both NAD+ and NADP+, and the preferred steroid substrate was the cholyl-coenzyme A conjugate rather than free cholic acid. These results show that the BaiA proteins are novel 3α-hydroxysteroid dehydrogenases.
51 citations