[Increased levels of noradrenaline in hypothyroidism and its association with cardiovascular system function]

In a group of 10 athyroid subjects treated with thyroxine and triiodothyronine discontinuation of both hormones induced hypothyroidism. During its development on the 7th, 14th, 21st and 28th day systolic time intervals, the heart rate, blood pressure and noradrenaline and adrenaline plasma level were assessed. On the 7th day of hypothyroidism an increased index of the preejection time was recorded, and its value continued to rise throughout the investigation period. A reduction of the index value of the ejection time was also observed on the 7th day and during the subsequent period the value did not change any more. A decline of the heart rate was observed on the 7th day and subsequently the frequency was stable. The index of electromechanical systole was protracted on the 28th day. The systolic blood pressure declined on the 14th day and did not change afterwards. The diastolic pressure rose on the 28th day. The noradrenaline plasma level was elevated from the 21st day of hypothyroidism, the adrenaline level did not change during the decline of thyroid function. The authors discuss the mutual relationship of changes and evaluate the impact of the rise of the noradrenaline level in hypothyroid subjects.