Effect of hypophysectomy and starvation on the fine structure of vitellogenic oocytes in the newt, Triturus pyrrhogaster (Laur).
Hypophysectomy and starvation in Triturus pyrrhogaster result in a similar ultrastructural pattern of follicular atresia. The first detectable change in the oocytes is decrease in the size and number of microvilli. Subsequently the yolk precursor bodies (YPB) disappear from the micropinocytotic vesicles and the mitochondria degenerate. Finally the yolk platelets undergo decomposition. The smaller yolk platelets disintegrate by granulation, vacuolation and lobule formation. The larger platelets, after losing their superficial layer and the inner crystalline lattice, are surrounded by a laminated membrane complex. The pattern of yolk breakdown is comparable to that during development. A rather delayed effect is observed on the nucleolus of the oocytes. Pigment granules seem to play an important role in the proteolysis of the yolk.
D000818:Animals; D005260:Female; D007016:Hypophysectomy / Q000009:adverse effects*; D008854:Microscopy, Electron; D009865:Oocytes / Q000254:growth & development / Q000648:ultrastructure*; D010063:Ovum / Q000648:ultrastructure*; D012455:Salamandridae / Q000033:anatomy & histology* / Q000502:physiology; D013217:Starvation / Q000150:complications*; D013997:Time Factors