Discussion We investigated the effects of HC intake and treadmill running exercise on bone mass and strength in growing male rats. This study demonstrated that HC intake increases bone mass in both trained and untrained growing rats. Although these results were shown in both moderate and high protein intake groups, the level of these beneficial effects

on bone mass was similar for the two groups. The intake of a high protein diet containing HC may have no more beneficial effect on bone mass and strength on growing rats trained with running exercise than the intake of a moderate protein diet containing HC. In the present study, we showed the effect of HC intake and treadmill running exercise on adjusted BMC of lumbar spine and tibia. The adjusted BMC was higher in the exercise

groups (Casein20 + Ex, Casein40 + Ex, HC20 + Ex, and HC40 + Ex) than in the sedentary groups Autophagy inhibitor screening library (Casein20, Casein40, HC20, and HC40). Especially in the trained HC intake groups (HC20 + Ex, OICR-9429 manufacturer HC40 + Ex), those effects were strongly observed. Guillerminet et al. [21] had shown that the BMD for OVX mice fed with the diet including HC (porcine origin) was significantly higher as compared to OVX mice fed on a standard AIN-93N diet. Mizoguchi et al. [22] had also shown that the HC (marine fish origin) intake increased the level of serum osteocalcin (OC), a well-known marker of osteogenesis, along with the BMD and the bone strength of femur in OVX rats. The levels of serum hydroxyproline and glycine of the HC intake group were increased in those cases. These results suggest that dietary HC intake increases the level of serum amino acid (hydroxyproline and glycine), the important components of bone, which then increases the BMD and bone strength. Moreover, in vitro study, hydrolyzed selleck compound collagens (bovine, porcine, and fish

origin, respectively having Cytidine deaminase a molecular weight of 2 or 5 kDa) in osteoblasts had significant and dose-dependent increase in ALP activity, a well-known marker of osteogenesis [23]. These results suggest that dietary hydrolyzed collagen may increase bone formation. Although, our result did not show the difference of bone formation marker, we cautiously postulated that the beneficial effect of HC intake in this study could have acted on bone during growth phase since we assessed the bone markers by end-point experiment when being already adult bone. Taken together, these results suggest that HC intake has a beneficial effect on bone mass in growing rats and this effect is more beneficial for rats participating in treadmill running exercise. Our study also investigated whether the intake of a high protein diet containing HC has positive effects on bone mass and strength of growing rats trained with running exercise.