Proliferative activity of somatic cells during gonadal development in the Japanese pond frog,Rana nigromaculata
✍ Scribed by Tanimura, Akihiko ;Iwasawa, Hisaaki
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 812 KB
- Volume
- 259
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Abstract
Proliferative activities of gonadal somatic cells were examined autoradiographically during gonadal development in Rana nigromaculata. Both the germinal epithelium and the sexual cord appeared to be of coelomic epithelial origin, as indicated ultrastructurally by the observation that the 2 regions were covered with a common basal lamina. Cell‐proliferative activity was higher in the sexual cord than in the germinal epithelium at stage 29, suggesting that topographically specific active proliferation of coelomic epithelial cells contributed to the formation of the sexual cord. In the course of testicular development, high proliferative activity of the sexual cord was recognized until stage 32 (just after gonadal sex differentiation). At stage 43 (during metamorphosis), higher proliferative activity was noted in the germinal epithelium than in the sexual cord, and the germinal epithelium differentiated into seminiferous cords. There were no differences in proliferative activity between the germinal epithelium and sexual cord at stages 32 and 34 in the ovaries. At stage 43, there was higher proliferative activity in the germinal epithelium than in the sexual cord, and the germinal epithelium differentiated into follicular cells. These results suggest that both seminiferous cords and follicular cells are derived from germinal epithelium and that both pass through similar processes of development.