Blue whiting (Micromesistius poutassou) muscle protein hydrolysate with in vitro and in vivo antidiabetic properties

A blue whiting (Micromesistius poutassou) protein hydrolysate generated using Alcalase 2.4L and Flavourzyme 500L and its simulated gastrointestinal digestion (SGID) sample was assessed for antidiabetic potential in vitro and in vivo. In addition to inhibiting dipeptidyl peptidase-IV (DPP–IV), the hydrolysates mediated insulin and glucagon-like peptide-1 (GLP-1) release from BRIN-BD11 and GLUTag cells, respectively. No significant difference was observed in insulinotropic and DPP-IV inhibitory activity following SGID, while GLP-1 secretion increased significantly (p < 0.01). SGID resulted in a significant increase in membrane potential, intracellular calcium and cyclic AMP concentration (p < 0.001) versus a glucose control, indicating that insulin secretion may be mediated by the KATP channel-dependent and the protein kinase A pathways. Additionally, acute (90–120 min) and persistent (4 h) glucose-lowering effects of the blue whiting hydrolysate were observed in normal healthy mice. These results demonstrate that the blue whiting protein hydrolysate had significant metabolic effects relevant to glucose control in vivo.