Abstract
Four groups of rats were fed vitamin E deficient or supplemented diets containing 5.6% or 15.6% linoleic acid, respectively, for 100 days. The histological changes of the thyroid gland of these rats were light and electron microscopically examined. The results obtained are as follows: 1) The weight and cell height of the thyroid gland of vitamin E deficient rats did not show remarkable changes. The diameter of thyroid follicles was smaller in these rats than those of vitamin E supplemented control rats. 2) The follicular epithelial cells of the vitamin E deficient rats showed somewhat degenerated form and irregular arrangement. They contained small degenerated mitochondria, dilated sacs of endoplasmic reticulum, less developed Golgi apparatus and a large accumulation of lipofuscin granules. The re-absorptive figures of microvilli and absorbed lipid droplets disappeared in the deficiency. 3) The follicular epithelial cells of the vitamin E deficient rats treated with linoleic acid showed further remarkable degenerative changes; vacuolation of cells, increase of lysosomes and peroxisomes and accumulation of lipofuscin granules. Some follicular lumens contained cellular fragments fallen down from the follicular wall. 4) The thyrotrophic hormone cells of the pituitary gland of vitamin E, deficient rats were enlarged. The change resembles that in thyroidectomy.
