Seasonal changes in immunolocalization of inhibin/activin subnits and testicular activity in wild male raccoon dogs (Nyctereutes procyonoides)
2006
Weng, Q.(Beijing Forestry Univ. (China)) | ; Medan, M.S. | ; Xu, M. | ; Tsubota, T. | ; Watanabe, G. | ; Taya, K.
Thirty-four pairs of testes from wild adult raccoon dogs (Nyctereutes procyonoides) were obtained between September 2000 and May 2003. The cellular localization of the inhibin alpha and inhibin/activin (betasub(A) and betasub(B)) subunits in wild raccoon dog testes was investigated. The testicular weight and size and seminiferous tubule diameters were measured. There were marked seasonal variations in testicular weight and size and seminiferous tubule diameters, with values relatively low in September and high in March. Spermatogonia and primary spermatocytes were observed in September, and spermatogonia, spermatocytes, and round spermatids were present in January. All types of spermatogenic cells, including mature spermatozoa, were found in March, indicating that the breeding season is around March in Japan. Thereafter, spermatogonia and degenerating spermatocytes were observed in April. The sections of testes were immunostained by the avidinbiotin-peroxidase complex method (ABC) using polyclonal antisera raised against porcine inhibin alpha, inhibin/activin betasub(A) and inhibin/activin betasub(B). The inhibin alpha and inhibin/activin (betasub(A) and betasub(B)) subunits were only expressed in Leydig cells in September. On the other hand, the inhibin alpha, betasub(A), and betasub(B) subunits were observed in Leydig cells and Sertoli cells, but not in germ cells, in March, These results suggest that the testes of wild raccoon dogs have the ability to synthesize inhibins, and the cellular localization of inhibin/activin subunits showed season-related changes in the breeding and nonbreeding seasons.
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