Effects of estriol on cell viability and 1,25-dihydroxyvitamin D3 receptor mRNA expression in cultured human osteoblast-like cells.
It is clinically evident that administration of estriol (E3) increases the bone mass density of the lumbar vertebrae in postmenopausal women, and that combined treatment with estrogen and 1,25-dihydroxyvitamin D3 (VD3) increases femoral neck bone mass density compared with treatment with estrogen alone in postmenopausal osteoporotic women. However, the molecular mechanism whereby treatment with E3 affects osteoblast cell function is still unknown. This study was conducted first to examine the comparative effects of E3 and VD3 on the cell viability of cultured human osteoblast-like cells (HOS) and second to determine whether E3 affects VD3 receptor mRNA expression in HOS. The cell viability and VD3 receptor mRNA expression of cultured HOS were assessed by MTT assay and semi-quantitative reverse transcriptase-polymerase chain reaction with Southern blot analysis, respectively. The treatment with E3 increased the cell viability of cultured HOS compared with untreated control cultures. The increase in cell viability caused by the treatment with E3 was further augmented by the combined treatment with VD3. The addition of either E3 (3.52 x 10(-8) mol/l) or E3 (3.52 x 10(-7) mol/l) to cultured HOS for 24 h resulted in a fourfold and eightfold increase, respectively, in VD3 receptor mRNA expression in HOS, compared with that in untreated control cultures. These results suggest that E3 may up-regulate the cell viability of osteoblast cells, and that the concomitant treatment with E3 and VD3 further augments the cell viability being associated with an E3-induced increase in VD3 receptor mRNA expression in those cells.
Department of Obstetrics and Gynecology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
Y
Y
Yamanaka
H
H
Matsuo
S
S
Mochizuki
S
S
Nakago
S
S
Yoshida
T
T
Maruo
D002117:Calcitriol / Q000008:administration & dosage / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology; D004964:Estriol / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006801:Humans; D010006:Osteoblasts / Q000187:drug effects*; D015663:Osteoporosis, Postmenopausal / Q000517:prevention & control; D012333:RNA, Messenger / Q000032:analysis; D018167:Receptors, Calcitriol / Q000187:drug effects* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D012333:RNA, Messenger; D018167:Receptors, Calcitriol; D004958:Estradiol; D004964:Estriol; D002117:Calcitriol