Leptin, is a hormone that synthesized by fat tissue, has an important role to regulate energy balance and metabolism and thus body weight. The influence of acute exercise and chronic exercise training on circulating leptin and its relationship with hormonal and metabolic changes that induce energy balance had been noted by researchers. The purpose of this study was comparison of serum leptin(L) , cortisol(C) and testosterone(T) responses to one bout acute aerobic exercise in active and non-active men. In this semi-empirical study, 18 men in two groups: nine active ( 21 /88 ±1/36yr with 6/11± 1/45yr active training for the preceding) and nine non- active (22/2±1/64yr with nonspecific training for the preceding) were not taking any medication, and were free of cardiac, respiratory, renal, or metabolic diseases, volunteered. Blood samples were collected before and immediately after 12 minutes intensive running exercise (cooper aerobic test).The concentrations of L, C and T serum was determined by Chemiluminescence laboratory method by Elisa kits. For statistical analysis of data we used from T-test, ANOVA and pearson correlation methods by spss software version 16. The results were showed that immediately after exercise, leptin levels (active group) and testosterone (in both groups) significantly increased, however, not founded significant differences inleptin, cortisol and testosterone between two groups before and after exercise. Also at baseline and after immediately exercise the relationship between serum L with PBF, Vo2max, BMI, WHR, serum concentrations of C and T in each groups were not significant (P<0/05). One bout intensive aerobic exercise such as12 minutes running not create real changes in concentration of leptin serum in active and non-active men.
