Repetitive Administration of Thyrotropin-Releasing Hormone Results in Small Elevations of Serum Thyroid Hormones and in Marked Inhibition of Thyrotropin Response

摘要

Repetitive administration of thyrotropin-releasing hormone (TRH) to human subjects was used to produce small elevations of endogenous serum triiodothyronine (T3) and thyroxine (T4) levels and thereby to determine the effect of these small elevations on the serum thyrotropin (TSH) response to subsequent doses of TRH. Each subject received 13 consecutive doses of 25 μg TRH at 4-h intervals. Serum T3, T4, and TSH levels were measured before the 1st, 7th, and 13th doses (“basal levels”) and for the 4 h after each of these doses.