Dynamic change in plasma leptin level during the perioperative period

OBJECTIVE: To examine the association of plasma leptin level with insulin, which is known as a metabolic regulator of leptin, and various stress-related factors during the perioperative period. METHODS: Thirty-one patients undergoing gastrectomy were enrolled and blood samples were obtained preoperatively, intraoperatively, immediately after operation, and on the first and second postoperative days. RESULTS: The plasma leptin level showed a triphasic response. Immediately after operation, the leptin level was the lowest, while the serum cortisol and interleukin-6 (IL-6) levels had their peak (PHASE 1). On the first postoperative day, the leptin level had its peak with the serum cortisol and IL-6 level remaining elevated (PHASE 2). On the second postoperative day, while the serum cortisol and IL-6 levels still remained elevated, the plasma leptin level fell to the preoperative value (PHASE 3). The plasma leptin level correlated well with the insulin level at all time points during the study period. CONCLUSION: Our results suggest a possible role of leptin in harmonizing neuroendocrine and immune responses with energy balance.