Journal of Okayama Medical Association
Published by Okayama Medical Association

Full-text articles are available 3 years after publication.

無尾兩棲類腦下垂體ノ發生ニ就テ(特ニ青蛙Rhacophorus schlegeliiニ於ケル檢索)

河内 武 岡山醫科大學解剖學教室胎生學研究室
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Although the literature dealing with the development of the hypophysis is voluminous, there is still a great deal of confusion concerning the cradle of the anlage of the epithelial lobe of the hypophysis. An endless chain of discussion has been evoked by the question as to whether the epithelial hypophysis is derived from the entoderm or from the ectoderm, or whether it is compounded of elements derived from both of these germ layers. On account of these discrepancis, the auther investigated the development of the hypophysis of the Anura, especially on Rhacophorus schlegelii, in comparison with previous results. Most of the materials were fixed in formalin-alcohol fluid, and stained with borax-carmine. After subsequent treatment in the usual manner, the specimens were embeded in paraffin, trimmed and cut in transverse serial sections and longitudinal serial sections of 10.0 and 20.0 microns' thickness. Some sections were stained with eosin-hämatoxyliu. A number of models were prepared according to Born-Peter's method of waxplate reconstruction. From the results of my experiments, the following summary and conclusions were made: 1) The hypophysis of Rhacophorus schlegelii consists of three epithelial lobes and a neural lobe. The epithelial hypophysis is derived from the ectoderm and consists of the pars anterior, the pars intermedia, and the pars tuberalis. 2) The pars anterior developer from the main central portion of the solid epithelial anlage. It is a flatish elliptical shape except in the case of the early stages, and lies caudal and ventral to the other lobes of the hypohysis. It moves caudally at an early stage, in the adult it connects with the infundibulum indirectly through the pars intermedia and the pars neuralis. 3) The pars intermedia is derived from the dorso-caudal region of the solid epithelial anlage. It has a long axis extending from side to side, and lies between the pars anterior and the pars neuralis. 4) The pars tuberalis arises from the pars lateralis which developes from the pars anterior. In the early stages it connects with the pars anterior but later on becomes detached, forming two epithelial disks lying close under the ventral wall of the infundibulum. 5) The pars anterior is the largest of three epithelial lobes, the pars intermedia the next smaller and the pars tuberalis the smallest. 6) The pars neuralis devolopes from the caudal tip of the infundibulum. It has a long axis extending from side to side and connects with the crauio-dorsal region of the pars intermedia.