抄録
Testicular development and hormone levels of triploid males of rainbow trout were compared with those of diploid males during three consecutive seasons. Changes in the levels of serum sex steroid hormones (testosterone, 11-ketotestosterone, and 17α, 20β-dihydroxy-4-pregnen-3-one) and pituitary and serum gonadotropin in triploids were similar to those in diploids. Although meiotic division first occurred in the July testes of both triploids and diploids, subsequent spermatogenesis was markedly delayed in the testes of triploids. During the natural spermiating season, a large number of atretic figures of spermatogenic germ cells were found in the testes of triploids with a sudden decrease in the gonadosomatic index. The amount of sperm was markedly less in triploids than in diploids. Some necrotic cells were invested by hypertrophied Sertoli cells lining the inner wall of the lobular lumen. Taken together, these results suggest that the cause of abnormality of spermatogenesis in triploids is the disruption of meiosis due to the odd number of chromosome sets.
