Register for Aromatase activity helps to maintain bone health after menopause
MenopauseJanuary 22, 2004
2004 JAN 22 - (NewsRx.com & NewsRx.net) -- Aromatase activity helps to maintain bone health after menopause.
According to scientists writing in the Journal of Steroid Biochemistry and Molecular Biology, "we have mainly focused on the regulatory mechanism of cytochrome P450 aromatase in bone cells. Our previous study demonstrated a strong positive correlation of serum dehydroepiandrosterone sulfate (DHEA-S) and estrone (E1) with BMD in postmenopausal women but no correlation between serum estradiol (E2) and BMD in the same group. In addition, administration of DHEA to ovariectomized rat significantly increased BMD."
"These in vivo findings strongly suggested that circulating adrenal androgen may be converted to estrogen in osteoblast and may contribute to BMD maintenance. Actually, in cultured human osteoblast cells, DHEA was found to convert to androstenedione by 3beta-hydroxysteroid dehydrogenase (3beta-HSD) activity and then androstenedione to estrone through the apparent aromatase activity," said T. Yanase and colleagues, Kyushu University, Graduate School of Medical Sciences.
"The aromatase activity in cultured human osteoblast cells was significantly increased by dexamethasone (DEX). Interestingly, DEX and 1alpha,25-dihydroxyvitamin D-3 (VD3) synergistically enhanced aromatase activity as well as P450arom mRNA expression. A little stronger induction of aromatase activity by DEX and VD3 was observed in cultured human fibroblasts. The increase of the aromatase activity by DEX and VD3 was accompanied with the increase of luciferase activity of fibroblast cells transfected with Exon 1b-promoter-luciferase construct, but not of osteoblasts transfected with the same construct, suggesting a different regulatory mechanism of aromatase by DEX and 1alpha,25-dihydroxyvitamin D-3 (VD3) between these two cells despite the same promotor usuage."
"In human bone cells, intracrine mechanism through aromatase activity, together with a positive regulation of aromatase activity by glucocorticoid and VD3, may contribute to the local production of estrogens, thus leading to protective effect against osteoporosis especially after menopause. The effect of sex steroids (estrogen versus testosterone) in bone remodeling was also briefly reviewed based on several recent findings in this field," said investigators.
Yanase and colleagues published their study in Journal of Steroid Biochemistry and Molecular Biology (Aromatase in bone: roles of Vitamin D-3 and androgens. J Steroid Biochem Mol Biol, 2003;86(3-5):393-397).
For additional information, contact T. Yanase, Kyushu University, Graduate School of Medicine Science, Department Med & Bioregulatory Science, Higashi Ku, 3-1-1 Maidashi, Fukuoka 8128582, Japan.
The publisher's contact information for the Journal of Steroid Biochemistry and Molecular Biology is: Pergamon-Elsevier Science Ltd., the Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, UK.
The information in this article comes under the major subject areas of Endocrinology, Osteoporosis, Enzymology, and Menopause. This article was prepared by Women's Health Weekly editors from staff and other reports. Copyright 2004, Women's Health Weekly via NewsRx.com & NewsRx.net.
©Copyright 2004, Women's Health Weekly via NewsRx.com & NewsRx.net
