[Glucose and insulin levels in Wistar rats submitted to high fat diet and treatment with mimetic leptin peptides].

Introduction: Studies on leptin administration have demonstrated a reversion of insulin resistance, and that leptin produces effects in glucose metabolism.

Objective: Changes in the insulin and glucose concentrations in blood plasma was evaluated by intraperitoneal administration of mimetic leptin peptides in Wistar rats fed with high fat diet.

Materials And Methods: A control group of rats was defined that were fed with high fat diet and a control group with normal diet. Several treatments groups were fed with high fat diet and subjected to the administration of seven different mimetic leptin peptides, each one administered in four different concentrations. During the peptide administration the glucose concentrations were quantified and at the end the insulin concentrations.

Results: The average insulin concentrations in the control groups were similar; however, hyperinsulinemia was observed in the groups to which we administered the peptide denominated 83 at doses of 10 mg/kg and 20 mg/kg of body weight. All the treatment groups except the peptide denominated with the code 80 showed diminished glucose levels even in the cases without hyperglycemia. The greatest effect was observed with the peptide 116-130 of the mouse leptin and its human homolog, although without statistical differences with the other treatments.

Conclusion: Lectin peptides have no effect on the insulin plasma concentrations; however, an effect is evident in glucose levels. Additional research will be required to determine if leptin mimetic peptides influence the glucose metabolism or the expression, secretion, signaling mechanism and regulation of insulin.