Perichromatin granule-like granular structures in the nuclei of antral-follicular oocytes of the Chinese hamster

In the nuclei of antral-follicular oocytes of the Chinese hamster (Cricetulus griseus), numerous granular structures ranging from 60 nm to 250 nm in diameter were present in the nucleolar area, and a few were observed on the surface of heterochromatin materials and within the interchromatin space. When treated with bismuth staining en bloc after glutaraldehyde fixation (GA-Bi staining), these granular structures were shown to be composed of fine fibrils intensely contrasted with bismuth, indicating that these may be regarded as one type of perichromatin granule.