[Sympathetic participation in the control of thyroid function (author's transl)]

A sympathectomy of the left thyroid lobe was carried out in 17 guinea pigs by sectioning the inferior thyroid artery. Thirty days after the surgical procedure, the animals were killed and the thyroids, together with the trachea and esophagus, were collected for histological processing. Histological, caryometric, and folliculometric studies revealed that the nuclei and thyroid follicles of the operated lobe were significantly larger than in the control lobe. Five guinea pigs were subjected to a temperature of 2 degrees C for 10 hours prior to killing; the thyroid lobe of the control showed a significant increase in the size of the nuclei and follicles. The operated lobe, on the other hand, showed no change. These results favour the hypothesis that sympathetic innervation plays an important role in the normal functioning of the thyroid as well as in a stress situation caused by cold.