Oral recombinant methioninase inhibits diabetes onset in mice on a high-fat diet

Background/Aim: We have recently shown that oral recombinant methionase (o-rMETase) prevents obesity in mice on a high-fat (HF) diet. The present study aimed to determine if o-rMETase can inhibit the onset of diabetes in mice on a HF diet. Materials and Methods: The mice on a HF diet were divided into two groups: 1) HF+phosphate buffered saline (PBS) group; 2) HF+o-rMETase group. Results: The blood glucose level in the HF+PBS group increased to average of 201 mg/dl during the experimental period of 8 weeks. In contrast, the blood glucose level in the HF+o-rMETase group maintained an average of 126 mg/dl (p<0.01, HF+PBS vs. HF+o-rMETase). The glucose tolerance test showed a significant increase in tolerance in the HF+o-rMETase group at 120 min after glucose injection compared to the HF+PBS group (p=0.04). Visceral adipose tissue was significantly less in the HF+o-rMETase group than the HF+PBS group (p=0.05). There was no difference in insulin levels, cholesterol or triglycerides between the HF+PBS and HF+o-rMETase groups. Conclusion: o-rMETase inhibited the onset of diabetes as well as prevented obesity on a high-fat diet, offering a possibility of a new and easy-to-use alternative to severe dieting or insulin injections.