25 hydroxy-vitamin D3-1α hydroxylase expression and activity in cultured human osteoblasts and their modulation by parathyroid hormone, estrogenic compounds and dihydrotestosterone
| Autor: | S. Katzburg, Yosef Weisman, Naftali Stern, Dalia Somjen, Rona Limor, Fortune Kohen, O. Sharon, David Hendel, Niva Jaccard |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
medicine.medical_specialty
Endocrinology Diabetes and Metabolism Clinical Biochemistry Genistein Parathyroid hormone Biochemistry chemistry.chemical_compound Paracrine signalling Endocrinology Internal medicine medicine Humans Raloxifene RNA Messenger Autocrine signalling Molecular Biology Cells Cultured DNA Primers 25-Hydroxyvitamin D3 1-alpha-Hydroxylase Osteoblasts Base Sequence Dihydrotestosterone Estrogens Cell Biology chemistry Parathyroid Hormone Molecular Medicine Phytoestrogens medicine.drug Hormone |
| Zdroj: | The Journal of Steroid Biochemistry and Molecular Biology. 107:238-244 |
| ISSN: | 0960-0760 |
| DOI: | 10.1016/j.jsbmb.2007.03.048 |
| Popis: | Human osteoblasts (hOB) produce and respond to 1,25(OH)(2)D(3) (1,25D), suggesting an autocrine/paracrine system. We therefore examined hormonal modulation of the expression and activity of 25 hydroxy-vitamin D(3)-1alpha hydroxylase (1-Ohase) in hOB. Cells from pre- and post-menopausal women or men, were treated with estrogenic compounds and 1-OHase expression and activity were measured. 1-OHase mRNA expression was highest in pre-menopausal women hOB and was increased by all hormones tested. In post-menopausal hOB all hormones except biochainin A (BA) and genistein (G) increased 1-OHase mRNA expressions to less extent. In male-derived hOB only dihydrotestosterone (DHT) and carboxy BA (cBA) increased 1-OHase mRNA expression. 1,25D production from 25(OH)D(3) had a K(m) of approximately 769-400 ng/ml (1.92-1.07 microM) and V(max) of 31.3-17.4 ng/ml (0.078-0.044 microM/60 min/5 x 10(6)cells) respectively, and was increased by all hormones except raloxifene (Ral) with higher stimulation in pre- than in post-menopausal cells. Only BA was almost five times more potent in pre- rather than post-menopausal hOBs. In male hOB only DHT and cBA increased 1,25D production whereas estradiol-17beta (E(2)) had no effect and BA decreased it. These results provide evidence for the expression of 1-OHase mRNA and production of 1,25D in hOBs, which are age and sex dependent and are hormonally modulated. The role of this local autocrine/paracrine 1,25D system in bone physiology deserves further investigation. |
| Databáze: | OpenAIRE |
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