Suppression of serum thyrotropin (TSH) concentrations following thyroidectomy and cold exposure by passive immunization with antiserum to thyrotropin-releasing hormone (TRH) in rats.

Administration of antiserum to synthetic thyrotropin-releasing hormone (TRH) to thyroidectomized rats caused a significant depression of serum thyrotropin (TSH). Serum TSH and triiodothyronine (T3) responses to cold exposure (4 +/- 1 C) were abolished by administration of anti-TRH serum. In addition, synthetic TRH lost its biological activity when bound to the gamma globulin fraction from the anti-TRH serum. These observations provide evidence that TRH is involved in the mechanism of enhanced TSH secretion from the pituitary following thyroidectomy and cold exposure.