The qlucocorticoid hormone was injected in two groups of rabbits. A control group and a group suffered ex perimental stress by temprature elevation, long photoperiod and relative humidity. The spermatogenic cell cycle was analysed qualitatively and qualitati vely using the Sertoli cell ratio. Glucocorticoid im proved the process of the spermatocytogenesis and retarded the differentiation of the spermiogenesis in normal testicles. The hormone did not protect the testicles againest the experimental summer stress. Although the spermatocytogenesis quantitatively im proved, all type of spermatocytes were suffering either lysis or coagulative necrosis. The mature spermatids were necrosed.