Abstract

In 4 male and 4 female professional athletes whose ages ranged from 18 to 25, ACTH, cortisol, 18-OH-DOC, aldosterone, prolactin, GH and opioid peptides weremonitored before, during and after reaching their maximal physical effort. Theaim of this experiment was to investigate the actual biological significance of the pituitary hormone secretion under a stressful condition. All the ath- letes followed a similar training program and were submitted to a previously described experimental protocol in which maximum aerobic capacity was reached by means of a treadmill, and blood sampling was done before, during and after reaching their 100 aerobic vital capacity. All the assays were performed by validated, specific and sensitive RIA and RRA. The results demonstrated a prompt increase in ACTH, beta-endorphin, prolactin and growth hormone in re- sponse to the physical stress, with no obvious sex differences. GH radiore- ceptorassay showed, in both sexes, a low binding capacity of this hormone to link its receptor compared with the immunological activity detected by RIA, with an RRARIA ratio of less than one (under normal conditions the ratio is greater than one). From these results it is possible to speculate that stress leads to the synthesis and secretion of prohormones by the pituitary gland.It was also found that the pituitary responsiveness to stress is the same in both sexes. Verf.-Referat