title: Hyperkeratinization and hyperplasia of the forestomach epithelium in vitamin A deficient rats.
abstract: Specific pathogen free F-344 rats were kept on a vitamin A deficient diet for 3-5 months. After 3 months on this diet the forestomach epithelium showed a mild atrophy. Stereological cytology showed a marked increase in the volume density of cytoplasmic filament bundles and decrease in the volume density of non-bundled cytoplasmic filaments. The volume fraction of keratohyalin granules increased whereas the volume fraction of membrane coating granules decreased. Some animals maintained for 4-5 months on the hypovitaminic diet exhibited the same mild atrophic forestomach epithelium accompanied by hyperkeratinization. Others showed a marked epithelial atrophy and 4 out of 12 animals revealed a marked hyperplasia with increased 3H thymidine labeling index and several papillomatous proliferations. Although many of these alterations reflect a decrease in proliferation as well as hyperkeratinization, the latter changes were not unlike those produced by known carcinogens, and support the putative important role of vitamin A in both carcinogenesis and chemoprevention.
mesh_terms: D000818:Animals; D004848:Epithelium / Q000032:analysis; D005260:Female; D006965:Hyperplasia; D007633:Keratins / Q000032:analysis*; D008854:Microscopy, Electron; D051381:Rats; D011916:Rats, Inbred F344; D013270:Stomach / Q000473:pathology* / Q000648:ultrastructure; D014802:Vitamin A Deficiency / Q000473:pathology*
chemical_list: D007633:Keratins