Figure 3

Npt2a determines the effects of Vitamin D3 on bone remodeling markers. Circulating bone markers, including osteocalcin, PINP, TRAcP 5b, and CTX-1 were measured in WT and Npt2a−/− mice after 4 days of treatment with either a vehicle or vitamin D3 (n = 6 per genotype). (a & b) Both genotypes show a small but significant increase in osteocalcin levels independent of treatment. (c & d) Vitamin D3 decreased plasma PINP independent of genotype. (e & f) In both genotypes, vehicle treatment slightly but significantly decreased plasma TRAcP 5b levels but vitamin D3 only significantly increased TRAcP 5b in WT mice. (g & h) Vitamin D3 treatment increased CTX-1 levels in both genotypes but to a significantly greater extent in Npt2a−/− mice. Male mice were used in these studies. In addition to single data summary data are shown and are expressed as mean ± SEM and were analyzed by repeated-measures two-way ANOVA followed by Tukey’s multiple comparisons test. *P < 0.05 vs WT same time point, #P < 0.05 vs baseline same genotype, §P < 0.05 vs vehicle same genotype and time point.