[Effects of progestin on proliferation and differentiation of osteoblasts].
OBJECTIVE
To study the effects of progesterone and levonorgestrel (LNG) on proliferation and differentiation of human normal osteoblasts and human osteosarcoma cell line MG-63.


METHODS
Cell proliferation was tested by 3-[4,5-Dimethylthiazolzyl]-2,5-Diphenyl Tetrazolium Bromide (MTT) assay. The expression of c-fos, c-jun and osteocalcin was measured by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) or immunocytochemistry.


RESULTS
Compared to the control group, progesterone at concentrations of 10(-10) mol/L, 10(-8) mol/L and 10(-6) mol/L increased the proliferation of human osteoblasts by 9.8%, 23.0% and 32.8% respectively and that of MG-63 cells by 7.8%, 15.6% and 21.8% respectively. LNG at concentrations of 10(-10) mol/L, 10(-8) mol/L and 10(-6) mol/L increased the proliferation of human osteoblasts by 12.5%, 21.9% and 32.8% respectively and that of MG-63 cells by 9.6%, 14.4% and 23.0% respectively. Progesterone and LNG upregulated c-fos and c-jun mRNA and protein in a dose-dependent manner. Likewise, progesterone and LNG increased the expression of osteocalcin mRNA in human osteoblasts by 12.2%, 23.7%, 45.5% and 18.6%, 32.1%, 60.3% respectively. The effects of LNG were greater than those of progesterone. Meanwhile, the expression of osteocalcin mRNA in MG-63 cells was not influenced by either progesterone or LNG.


CONCLUSIONS
Progesterone and LNG stimulate proliferation of osteoblasts and increase the expression of c-fos, c-jun and osteocalcin.
Liang
Min
M
Department of Endocrinology, First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China.
Liao
Er-yuan
EY
D002454:Cell Differentiation / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016912:Levonorgestrel / Q000494:pharmacology; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D015675:Osteocalcin / Q000235:genetics; D012516:Osteosarcoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D011374:Progesterone / Q000494:pharmacology; D011372:Progestins / Q000494:pharmacology*; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis / Q000235:genetics; D016755:Proto-Oncogene Proteins c-jun / Q000032:analysis / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
D011372:Progestins; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D015675:Osteocalcin; D011374:Progesterone; D016912:Levonorgestrel