Effect of unilateral or bilateral thyroidectomy on TRH content of hypothalamus halves.

The effect of uni- or bilateral thyroidectomy on the thyrotropin-releasing hormone (TRH) content of the mediobasal hypothalamus (MBH) of the two sides was studied in male rats. Both right- and left-side hemithyroidectomy resulted in a significantly increased TRH content in both halves of the MBH. In addition, the total TRH content rise of the MBH was higher after unilateral than after bilateral thyroidectomy. The mechanism of action of uni- or bilateral thyroidectomy on the hypothalamic TRH content is discussed.