シマドジヨウに於ける人工排卵について
1950 年 1 巻 1 号 p. 1-7
詳細
1950 年 1 巻 1 号 p. 1-7
On Artificial Ovulation in the Spinous Loath.
1. Changes occurring in the ovarian eggs of the spinous loaches which were injected with frog pituitary suspension during the breeding season were observed microscopically on sections of fixed material.
At 25°C the changes found in most of the eggs were as follows:
Yolk granules surrounding the germinal vesicle begin to dissolve two hours after the injection. The germinal vesicle is moved towards the animal pole one hour later. At the fifth hour after the injection it disappears and all of the yolk granules contained in the egg show a tendency to become larger by fusion with neighboring ones. At that time the eggs begin to become semi-transparent.
The first maturation spindle is observed in the eggs which were fixed six hours after the injection. The metaphase spindle of the second maturation division is formed one hour later. About that time ovulation begins to occur in the spinous loaches.
2. The unfertilized egg shed into water gives off the second polar body and forms the female pronucleus in the egg as the fertilized does.
3. When fragments of the ovaries of spinous loaehes are immersed in frog pituitary suspension in vitro, ovulation occurs. One of the eggs extruded from the fragments cleaved normally after insemination.
