Response of Normal, Hypothyroid and Hypothalamo-Pituitary Insufficient Children to Synthetic Thyrotrophin-Releasing Hormone

Abstract

Thyrotrophin-releasing hormone (TRH) was synthesized by the solid phase technique, administered to 13 children, and the time-course changes in the serum level of thyroid-stimulating hormone (TSH) assessed. In eight normal children, peak levels of TSH occurred 20 min after the injection, and circulating TSH remained significantly raised for 60 min. In three hypothyroid children, the increase in serum TSH was much greater than in normal children, suggesting the existence of large pituitary TSH stores. In two hypopituitary children with TSH deficiency, TSH reserves seemed normal. One of these patients had a craniopharyngioma; after operation, the increase in serum TSH was reduced. These results show that assay of serum TSH after administration of synthetic TRH provides a test which distinguishes pituitary from hypothalamic defects affecting TSH secretion.

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

“…TRH deficiency appears, therefore, to have been confirmed by producing chemical euthyroidism by replacement of the presumedly missing hormone. Several other patients, however, have been described who, like L. C., and K. C., had low serum thyroid hormone and low-normal basal TSH levels and normal TSH responses to a single dose of TRH (18)(19)(20)(21)(22). The marked fall in the initially subnormal TSH response to TRH in M. J., the patient with presumed pituitary insensitivity to TRH, was accompanied by rises in serum T3 and T4, but rises so small that the final levels were still subnormal.…”

Effect of Thyroxine on the Inactivation of Thyrotrophin‐releasing Hormone by Rat and Human Plasma

“…The importance of such a study may be indicated by the widespread use of TRH in clinical studies, especially to test pituitary response to TRH, leading to differentiation between the pituitary and hypothalamic hypothyroidism (Hershmann & Pittman, 1970;Fleischer et al, 1970Fleischer et al, , 1972Milhaud et al, 1971;Anderson et al, 1971a, b;Gual et al, 1972).…”