[Serotonin concentration in the hypothalamus following alteration of pituitary thyrotropic function].

The hypothalamic serotonin content in the altered pituitary thyrotropic function was determined in mature male rabbits by the fluorescent method. No distinct correlation was found between the intensity of the pituitary thyrotropic function and serotonin level in the hypothalamus. Intensification of the hypophysial thyrotropic function under the effect of 6-methylthiouracil or partial thyroidectomy was accompanied by a rise in serotonin concentration, while in aseptic inflammation in the thyroid gland, or in combination of the upper cervical sympathetic ganglia ablation with chlorpromazine administration this adenohypophysial function proved to increase without any significant shifts in the hypothalamic serotonin level. The mentioned findings suggest that the role of serotonin in the hypothalamic regulation of the hypophysial thyrotropic function could not be considered as determining.