Circulating Leptin, Ghrelin, Glucose, Insulin, C-Peptide, GH, IGF-1, Cor- tisol, and Interleukin-6 Concentrations, and the Systemic Stress Response to Uncomplicated Surgical Injury

The mechanisms initiating, regulating and sustaining the systemic stress response to a surgical injury have not all been identified yet. Recent studies point to the adipose tissue as a major endocrine system, the hormones of which influence energy homeostasis, glucose and lipid metabolism, vascular homeostasis, and immune response. Essential elements of this control system are leptin and ghrelin. The purpose of the present study was to compare the patterns of leptin and ghrelin secretion in different perioperative periods in patients undergoing elective cholecystectomy, and to relate the changes in circulating leptin or ghrelin to concomitantly occurring changes in glucose, insulin, C-peptide, growth hormone (GH), insulin-like growth factor (IGF)-1, total cortisol, free cortisol index, and interleukin-6, and other clinical parameters. Thirty patients were included in the study. Blood was sampled at seven time points between one hour prior to the induction of anesthesia (first observation) to approximately 24 hours later. Both leptin and ghrelin displayed a parallel decrease in concentrations from baseline in the intra-and postoperative periods, with a parallel return to baseline on the morning of the first postoperative day. However, at each perioperative period the leptin trend was not associated with that of other substances(including ghrelin).Likewise, the ghrelin time trend was independent of other study variables (including leptin). What triggers this response remains unknown but this study implies that it is unlikely to be the hypothalamicpituitary-adrenocortical, GH/IGF-1, or glucose homeostatic axis, or proinflammatory cytokines.