Identification of keratohyalin in freeze-fracture replicas of rat buccal epithelium.

In freeze-fracture replicas of rat cheek epithelium structures representing various forms of keratohyalin granules as seen in stained thin sections have been identified. Discrete spherical granules present in nuclei and cytoplasm are represented in replicas by aggregates of 6 nm particles, and composite granules by similar aggregates associated with a homogeneous component. The observations tend to support the concept of the structural heterogeneity of keratohyalin granules.