Figure 4.

Differential measures of collagen incorporation and synthesis with estrogen replacement and exercise. The rate of (A) collagen incorporation of proline into the patellar tendon or (B) the appearance of the N-terminal propeptide of collagen I in post-menopausal women ± estrogen replacement therapy (ERT) and exercise. Note that with ERT collagen incorporation is higher in the same women where collagen synthesis is repressed. Further, exercise tends to decrease collagen incorporation and synthesis in controls, whereas ERT users show no effect on incorporation or a large drop in collagen synthesis. Symbols (*P < 0.01, **P < 0.001) show significance determined by unpaired t-test Control vs. ERT. These data suggest that there is a large methodological discrepancy between the two measures. Adapted from Hansen et al. (2009b).