Electrothyreogram, Blood Iodine and Thyroid Iodine during Stimulation of the Sympathetic

Abstract

Summary.Electrothyreograms elicited in decerebrate cats by faradic stimulation of the sympathetic or by injection of adrenaline have been recorded with the aid of a string galvanometer and a directly‐coupled balanced push‐pull amplifier. The aim of this work has been to correlate blood iodine, thyroid iodine and electrothyreograms, and, if possible, to obtain evidence for sympathetic control of the thyroid gland.Blood iodine has been determined by a modified Leipert method, described in detail in a previous commrnication (Helin, Zilliacus, Unonius, 1939).Blood iodine was found to be increased after stimulation of the sympathetic as well as after injection of adrenaline. In the former case the increase averaged 36.9%, in the latter case 47.1%. Controls with uustimulated animals showed that decerebration and operation around the thyroid did not as such influence the iodine concentration of the blood.The increase in blood iodine after stimulation was found to be accompanied by a decrease of thyroid iodine amounting to about 85.4%.Stimulation bringing about these changes in the iodine concentration of the gland and the blood is always accompanied by an electrothyreogram which accordingly is regarded as an index of secretory activity in the gland.