Mature male rat weighing approximately 200g was injected every 10 days interval about 20㎎ of testosterene propionate for 50 days to study the influence of adrenal gland on the functional changes of testis. Weight and histological changes of adrenal gland were as follows; 1. Weight of adrenal gland was increased as increasing treatment time and was significantly (p$lt;0.05) different after 30 days of treatment. 2. The increases of zona fasciculata and zona reticularis were significantly (p$lt;0.05) different after 30 days and 40 clays, respectively, and adrenal medulla was decreased and was significant (p$lt;0.05) after 30 days of treatment. 3. Vacuolization in zona fasciculata and zona reticularis was recognized after 30 days, hypertrophy of cells occurred after 400days and enlargement phenomenon of nucleus was showed after 40 clays. But no any typical changes were observed in zona glomerulosa in adrenal cortex and medulla. 4. The occurrence of hypertrophy and histological changes in zona fasciculata and zona reticularis was due to the sexual hormone which was an obstacle to synthesis of adrenocortical hormone, thus reducing blood Level of this hormone. Consequently, A.C. T.H. secretion from hypophysis was accelerated. It is believed that cell which forms the zona fasciculata became hypertrophy and zona reticularis was also thicken under these conditions.