[Scanning electron microscopic study of the changes of the luminal surface of rat thyroid epithelial cells following exposure to cold for 6 to 48 hours (author's transl)].

Scanning electron microscopic observations of thyroid follicle cells of rats exposed to 4 degrees C for 6 to 48 hours were found to show an increased number of apical microvilli in comparison to those of controls kept at 22 degrees C. These ultrastructural differences--which were statistically significant 48 hours after start of the experiments--are related to stimulation of thyroid gland activity by exposure to cold.