Abstract: | It has been reported on the occurence of vegetative neurons in the stroma of the sand rat (Psammomys obesus) thyroid gland. The cells show all the typical signs of autonomic nerve cells. In contrast to neurons appearing in the pancreas of the sand rat, the neurons in the thyroid gland occur in most cases as singular neurons. The importance of the sympathetic innervation for the thyroid function has been discussed and the close relationship between thyroid hormone secretion and biogenic amines localized in the thyroid mast cells has been described as well. |