Structural changes in the thyroid gland of buffalo following administration of thiouracil

The effects of a goitrogen (thiouracil) on the structural variations of the thyroid gland were studied in male buffalo calves. Following the treatment, the thyroid became enlarged and both the weight and the size of the gland were significantly increased (P less than 0.01). Hyperplasia and hypertrophy of the gland were correlated with a significant increase of thyroidal uptake of 131I. The height and number of the follicular cells were significantly increased (P less than 0.01). The follicles were small and had vacuolations in the colloid. The colloid content of the follicles became reduced. The vascularity of the gland was appreciably increased.