The co-ordinated cytokine/hormone response to acute injury incorporates leptin

Recent studies have implicated leptin as a "stress" hormone and highlighted its association with increases in inflammatory cytokines, C-reactive prote in and cortisol. In order to investigate the exact temporal leptin response to stress we undertook a detailed longitudinal study of circulating leptin concentrations during the well defined surgical injury of cholecystectomy. Circulating concentrations of cortisol, free fatty acids, leptin and C-rea ctive protein were measured at 3, 6, 9, 12, 18, 24, 48 and 72 h from the st art of surgery in nine patients. There was a significant correlation betwee n baseline concentrations of leptin and BMI (r = 0.893, P < 0.001). Over th e 72 h from the start of surgery there were significant (P < 0.05) increase s in the concentrations of all analytes (peak median concentrations); corti sol (6 h), free fatty acids (9 h), leptin (18 h) and C-reactive protein (48 h), Interestingly the timing of the leptin peak at approximately 18 h afte r an acute inflammatory stimulus is exactly the same as previously reported for interleukin 6. These data support the suggestion that the relationship between cortisol and leptin mirrors that of cortisol and another cytokine, interleukin 6, i,e, stimulatory in acute and suppressive in chronic situat ions. They also imply a physiological role for leptin in acute injury. (C) 2000 Academic Press.