Carboxyl-terminal parathyroid hormone peptide (53-84) elevates alkaline phosphatase and osteocalcin mRNA levels in SaOS-2 cells.
Previous findings in our laboratory have shown that hPTH-(53-84) stimulates alkaline phosphatase activity in dexamethasone-treated ROS 17/2.8 cells. In the present study, we examined the effects of hPTH-(53-84) and hPTH-(1-34) on the expressions of alkaline phosphatase, osteocalcin, and collagen type I mRNA levels in the human osteosarcoma cell line SaOS-2. The effect of hPTH-(53-84) on alkaline phosphatase and osteocalcin message levels was dose dependent (ANOVA, p < 0.005 and p < 0.001, respectively), with significant stimulation observed at 10 nM. Treatment with 10 nM hPTH-(53-84) for 24 h resulted in significant 2- and 1.4-fold increases in mRNA levels for alkaline phosphatase and osteocalcin, respectively (p < 0.05), but had no effect on collagen type I expression. The increased alkaline phosphatase mRNA levels was associated with a 1.5-fold increase in enzyme activity (p < 0.05). In contrast, under similar incubation conditions, hPTH-(1-34) had no significant effects on alkaline phosphatase or osteocalcin mRNA levels. On the other hand, hPTH-(1-34) had dose-dependent stimulatory effects on collagen type I mRNA levels (ANOVA, p < 0.001), 10 nM hPTH-(1-34) stimulating collagen type I expression 1.6-fold (p < 0.05). The results indicate that carboxyl-terminal hPTH-(53-84) has direct and unique biologic effects in human osteoblast-like cells in culture.
Division of Endocrinology and Metabolism, St. Michael's Hospital, Toronto, Ontario, Canada.
M K
MK
Sutherland
L G
LG
Rao
J N
JN
Wylie
A
A
Gupta
H
H
Ly
J
J
Sodek
T M
TM
Murray
D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D003094:Collagen / Q000235:genetics / Q000378:metabolism; D006801:Humans; D010006:Osteoblasts / Q000378:metabolism*; D015675:Osteocalcin / Q000235:genetics / Q000378:metabolism*; D010281:Parathyroid Hormone / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D019379:Teriparatide
D010281:Parathyroid Hormone; D010446:Peptide Fragments; D012333:RNA, Messenger; C035453:parathyroid hormone (53-84); D015675:Osteocalcin; D019379:Teriparatide; D003094:Collagen; D000469:Alkaline Phosphatase