Effect of collagen peptides rich in hydroxyprolyl-glycine on anabolic signals in mouse skeletal muscle

Collagen peptides (CPTs) increase muscle mass with resistance exercise training. However, little is known regarding the effect of CPT administration on anabolic signals in skeletal muscle. In this study, we prepared two types of CPTs, one rich in hydroxyprolyl-glycine (CPT-A) and the other rich in hydroxyprolyl-glycine, prolyl-hydroxyproline, and alanyl-hydroxyprolyl-glycine (CPT–B) and investigated the effects of these peptides on skeletal muscle mTORC1 in mice. Initially, the effects of individual administration of each CPT were investigated. CPT-B increased the expression of phosphorylated rpS6 at 180 min post-administration which was not observed after the administration of whey protein. CPT-A did not induce any significant changes in mTORC1 signaling. Subsequently, their combined effects with whey protein were evaluated. However, the delayed activation was not observed under these conditions. These findings suggest that the CPT-B alone has the potency to activate mTORC1 progressively over time, with a slower onset than whey protein. • Plasma PO, OG, and AOG concentration were increased by administration of each CPT. • Collagen peptides rich in PO, OG, and AOG activated mTORC1 with a delayed response. • Plasma peptide increased even when CPTs were administered with whey protein. • Mixing CPTs with whey protein abolished the delayed activation of mTORC1.