Objective: The effect of hyperthermia on pituitary – gonadal axis of adult male albino rats exposed to high temperature (40 ± 1°C) for 12 hours was investigated. The protective role of vit. C in hyperthermia exposed rats was also studied. Animals and Methods: Thirty adult male rats, about 3 months old, were used. They were divided into three equal groups and separated into two rooms. The rats in the first room (gp 1/ control) were maintained under 25 ± 5°C environmental temp. Rats of second room (gp 2 & 3) were subjected to 40 ± 1°C for 12 hours. Rats of gp 1 & 2 were fed on a normal commercial rat ration while, rats of gp3 were fed on the same ration supplemented with vit. C. Serum, testicular and pituitary levels of testosterone, LH, FSH and PRL were evaluated in all rat groups. Histopathological examination of testes were evaluated after heat exposure. Results: obtained revealed a significant lowered levels of testicular testosterone in gp 2 as compared with that of (gp 1 & 3). Serum levels of Testosterone, LH and FSH were significantly decreased and PRL level was significantly increased in gp 2 as compared with (gp 1 & 3). In addition, pituitary Levels of FSH or LH were significantly decreased and PRL level was significantly increased in gp 2. Histopathological examination revealed disorganization of semineferous tubules of the testes in gp 2. Conclusion: avoidance of hyperthermia is very important to maintaine a proper pituitary - gonadal axis. Vit.C was found to counteracts the adverse effects of hyperthermia. Also, rat model could be considered as a basis to investigate the effects of hyperthermia on human males working in areas of higher heat exposure.

hyperthermia, pituitary - gonadal axis , testis, Vit.C, rats