Estrogen-mediated regulation of CYP7B1: A possible role for controlling DHEA levels in human tissues

Title

Estrogen-mediated regulation of CYP7B1: A possible role for controlling DHEA levels in human tissues

Creator

Tang W J; Eggertsen G; Chiang J Y L; Norlin M

Publisher

Journal of Steroid Biochemistry and Molecular Biology

Date

2006
2006-07

Description

The current study examines regulation of CYP7B1, a DHEA 7 alpha-hydroxylase, by sex hormones. Transfection with estrogen receptor alpha and treatment with 17 P-estradiol in human embryonic kidney 293 cells significantly increased CYP7B1 catalytic activity and mRNA, and stimulated a human CYP7B1 reporter gene. Transfection with estrogen receptor P showed similar but less significant effects. In the absence of receptors, 17 P-estradiol suppressed CYP7B1 activity, suggesting that estrogenic effects may be different in cells not expressing receptors. Quantitation of CYP7B1 mRNA in adult and fetal human tissues showed markedly higher CYP7B1 mRNA levels in fetal tissues compared with the corresponding adult ones, except in the liver. This indicates a tissue-specific, developmental regulation of CYP7B1 and suggests an important function for this enzyme in fetal life. DHEA secreted by fetal adrenals is an essential precursor for placental estrogen formation. Since CYP7B1 diverts DHEA from the sex hormone biosynthetic pathway, estrogen receptor-mediated up-regulatio of CYP7B1 should lead to less DHEA available for sex hormone synthesis and may help to maintain normal levels of estrogens and androgens in human tissues, especially during fetal development. Regulation by estrogens may also be of importance in other processes where CYP7B1 is involved, including cholesterol homeostasis, cellular proliferation, and CNS function. (c) 2006 Elsevier Ltd. All rights reserved.

Subject

7-alpha-hydroxylase; alzheimers-disease; bile-acid biosynthesis; Biochemistry & Molecular Biology; CYP7B1; dehydroepiandrosterone 7-hydroxylase; DHEA; Endocrinology & Metabolism; estrogen; fetal development; gene-expression; human oxysterol 7-alpha-hydroxylase; prostate; rat; receptor-beta; sex hormone biosynthesis; transcriptional regulation; vascular dementia

Format

Journal Article

Search for Full-text

Users with a NEOMED Library login can search for full-text journal articles at the following url: https://libraryguides.neomed.edu/home

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

42-51

Issue

1

Volume

100

Citation

Tang W J; Eggertsen G; Chiang J Y L; Norlin M, “Estrogen-mediated regulation of CYP7B1: A possible role for controlling DHEA levels in human tissues,” NEOMED Bibliography Database, accessed June 21, 2021, https://neomed.omeka.net/items/show/7283.

Social Bookmarking