title: Proliferative lesions in thyroid follicular cells of dwarfs derived from Wistar Hannover GALAS rats.
abstract: We observed spontaneous dwarfism among Wistar Hannover GALAS rats, caused by primary hypothyroidism. The dwarf (D) rats showed markedly high serum thyroid-stimulating hormone (TSH) values. In this study, we investigated the incidence and histopathological characteristics of the proliferative lesions of the thyroid follicular cells in our D rats. Gross enlargement of thyroid and histological vacuolar change of the thyroid follicular cells with age-related progression suggesting diffuse hypertrophy/hyperplasia were seen in all the D rats. In addition, focal proliferative lesions-namely hyperplasias, activated hyperplasias, adenomas, and adenocarcinomas--were seen in D rats aged over 50 weeks. Taken together, these results suggested that the sustained stimulation of elevated levels of serum TSH caused and enhanced diffuse hypertrophy of thyroid follicular cells and subsequent development of focal proliferative lesions.
authors.affiliation: 1Pathology Department, Kashima Laboratory, Nonclinical Research Center, Mitsubishi Chemical Medience Corporation, Ibaraki, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kokoshima
authors.forename: Takuya
authors.initials: T
authors.lastname: Doi
authors.forename: Naoaki
authors.initials: N
authors.lastname: Yamada
authors.forename: Minoru
authors.initials: M
authors.lastname: Tsuchitani
mesh_terms: D000818:Animals; D004392:Dwarfism / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006965:Hyperplasia / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D007037:Hypothyroidism / Q000473:pathology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013961:Thyroid Gland / Q000166:cytology / Q000473:pathology; D013972:Thyrotropin / Q000097:blood
chemical_list: D013972:Thyrotropin
keywords: dwarfism; hypothyroidism; neoplasm; spontaneous; thyroid; thyroid dysplasia.; vacuolar change