[Effects of different human parathyroid hormone 1-34 administration on SaoS-2 cells].
OBJECTIVE
To observe the effects of different human parathyroid hormone 1-34 (hPTH1-34) administration on SaoS-2 cells, and explore the mechanism of bone formation improvement.


METHODS
Each cycle covered 48 h. SaoS-2 cells were continuously or intermittently stimulated by 50 ng/ml hPTH1-34 for 1, 3, 6, 12, and 24 h in each cycle. Total RNA was extracted by Trizol kit. Alkaline phosphatase (ALP), osteocalcin or bone Gla-containing protein (BGP) and cyclic adenosine monophosphate (cAMP) levels were measured by chemical method, radioimmunoassay and competitive protein binding method, respectively. c-fos gene expression was semi-quantified by reverse transcription polymerase chain reaction (RT-PCR).


RESULTS
ALP level was time-dependently increased in 1, 3 and 6 h stimulation, especially in 3 and 6 h (compared with control, P < 0.01; P < 0.05 or P < 0.01 compared with continuous stimulation). The cAMP level was time-dependently increased in 3 and 6 h incubation (P < 0.05 compared with control and continuous stimulation). Intermittent hPTH1-34 stimulation had more effects on cAMP level than continous action (P < 0.001). hPTH1-34 intermittent stimulation of 1, 3, and 6 h enhanced c-fos gene expression time-dependently.


CONCLUSIONS
Intermittent hPTH1-34 stimulation has a stronger effect on osteoblast than continuous action, especially in 3, 6 h in each cycle intermittent stimulation. The synchronous responses of c-fos, ALP and cAMP to hPTH1-34 suggest that hPTH1-34 affect Saos-2 cells through cAMP dependent protein kinase A (PKA) pathway and c-fos gene paly an important role.
Li
Mei
M
Department of Endocrinology, PUMC Hospital, CAMS and PUMC, Beijing 100730, China. limeilzh@yahoo.com
Meng
Xun-wu
XW
Zhou
Xue-ying
XY
Xing
Xiao-ping
XP
Xia
Wei-bo
WB
Liu
Huai-cheng
HC
D000469:Alkaline Phosphatase / Q000032:analysis; D002478:Cells, Cultured; D006801:Humans; D010006:Osteoblasts / Q000166:cytology*; D015675:Osteocalcin / Q000032:analysis; D010012:Osteogenesis / Q000187:drug effects; D012516:Osteosarcoma / Q000235:genetics / Q000473:pathology*; D010281:Parathyroid Hormone / Q000494:pharmacology*; D044162:Parathyroid Hormone-Related Protein / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology*; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics
D010281:Parathyroid Hormone; D044162:Parathyroid Hormone-Related Protein; D010446:Peptide Fragments; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D015675:Osteocalcin; D000469:Alkaline Phosphatase