Mk. Sutherland et al., CARBOXYL-TERMINAL PARATHYROID-HORMONE PEPTIDE (53-84) ELEVATES ALKALINE-PHOSPHATASE AND OSTEOCALCIN MESSENGER-RNA LEVELS IN SAOS-2 CELLS, Journal of bone and mineral research, 9(4), 1994, pp. 453-458
Previous findings in our laboratory have shown that hPTH-(53-84) stimu
lates 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, osteocalc
in, and collagen type 1 mRNA levels in the human osteosarcoma cell lin
e SaOS-2. The effect of hPTH-(53-84) on alkaline phosphatase and osteo
calcin message levels was dose dependent (ANOVA, p < 0.005 and p < 0.0
01, respectively), with significant stimulation observed at 10 nM. Tre
atment 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 osteoc
alcin, respectively (p < 0.05), but had no effect on collagen type I e
xpression. The increased alkaline phosphatase mRNA levels was associat
ed 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 oth
er hand, hPTH-(1-34) had dose-dependent stimulatory effects on collage
n 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 eff
ects in human osteoblast-like cells in culture.