Biochemical bone turnover markers and sex steroid concentrations in skeletally mature WT and F8^TKOmale mice. Biochemical indices of bone turnover (resorption and formation) were quantified in serum from 2-month-old and 6-month-old male and female C57BL6 WT and F8^TKO mice. The bone formation marker PINP in males at 2 months (A) and 6 months (C). The bone resorption marker CTX in males at 2 months (B) and 6 months (D). PINP in females at 2 months (E) and 6 months (G). CTX in females at 2 months (F) and 6 months (H). Data are expressed as boxplots (median + IQR) with Tukey whiskers. n = 10 WT and 6 F8^TKO male mice/group and 10 WT and 11 F8^TKO female mice at 6 months, and 10 WT and 12 F8^TKO male mice/group and 10 WT and 6 at F8^TKO female mice at 2 months. *P < .05 by Student t test. Quantitative analysis of 17β-estradiol and testosterone concentrations in serum from young and mature WT and F8^TKO male mice. (I-J) To quantify sex steroid concentrations, we measured 17β-estradiol in serum from female WT and F8^TKO mice at 2 months of age (I) and 6 months of age (J). (K-L) Testosterone was quantified in male mouse serum at 2 months of age (K) and 6 months of age (L). Data are expressed as boxplots (median + IQR) with Tukey whiskers. n = 10 WT and 6 F8^TKO male mice/group and 20 WT and 8 F8^TKO female mice at 2 months, and 10 WT and 6 F8^TKO male mice/group and 20 WT and 10 at F8^TKO female mice at 6 months. *P < .05, **P < .01, and ns by Student t test (female mice) or Mann-Whitney U test (male mice). One extreme (6-month-old male F8^TKO group outlier [11.6 ng/mL: Grubbs test, α = 0.05]) was removed from the statistical analysis but is shown on the graph.