HORMONAL RESPONSES IN STRENUOUS JUMPING EFFORT

In order to test the possibility for rapid responses of blood hormone levels in short-term supramaximal exercises, serum concentrations of c orticotropin (ACTH), cortisol (C), total testosterone (tT), free testo sterone (fT), growth hormone (GH), thyrotropin (TSH), free thyroxine ( fT(4)), free triiodothyronine (fT(3)), prolactin (PRL), insulin-like g rowth factor (IGF-I), and sex hormone-binding globulin (SHBG) were det ermined by RIA procedures in blood samples obtained before and immedia tely after a 60-s period of consecutive vertical jumps (Bosco test). T he study subjects were 16 Italian professional soccer players. Immedia tely after exercise, significant increases (p<0.05) were found in the concentrations of ACTH (by 39%), C (by 14%), TSH (by 20%), fT(3) (by 2 8%), fT(4) (by 30%), tT (by 12%), fT (by 13%), and SHBG (by 21%). Sign ificant changes were not detected in the blood levels of GH, IGF-I and PRL. Most pronounced testosterone responses were typical for persons of high jumping performance (the increase of serum tT correlated with average power output, r=0.61 and jumping height, r=0.66). The larger t he drop in power output during 60-s jumping, the higher was the thyroi d response: the difference in jumping height between the first and las t 15-s period correlated with increases in TSH (r=0.52) and in fT(4), (r=0.55). In conclusion, the obtained results indicate that in intense exercise, causing the rapid development of fatigue, rapid increases i n serum levels of hormones of the pituitary-adrenocortical, pituitary- gonadal and pituitary-thyroid systems occur.