著者

吉倉 真

出版者

社団法人日本動物学会

雑誌

動物学雑誌 (ISSN:00445118)

巻号頁・発行日

vol.72, no.1, pp.13-16, 1963-01-15

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The present study was undertaken with the object of determining whetehr the hypopysis has some connection with sex reversal in amphibians. Hypophysectomized or thyroidectomized frog larvae (Rana japonica) were treated with estrone (1mg/1) from 105 days of age for 45 days and thereafter maintained without estrone up to 225 days of age. In both groups of animals ovaries were not affected by estrone, but the testes, in most cases, were feminized (Figs. 1, 2). The hypophysis therefore had no connection with gonad feminization. After the treatment was stopped, feminized gonads of thyroidectomized larvae were restored to the testes, all of the ovocytes were destroyed, and the luteal-like bodies were formed (Fig. 3). On the other hand, feminized gonads of hypophysectomized larvae seemed to have evolved into the ovaries (Fig. 4). It seems probable that when the hormonal treatment is stopped, the hypophysis controls the developmental fate of the gonad feminized by the action of estrone.