Thyrotropin-Releasing Factor (TRF) Effect on Secretion of Human Pituitary Prolactin and Thyrotropin in Children and in Idiopathic Hypopituitary Dwarfism: Further Evidence for Hypophysiotropic Hormone Deficiencies

Synthetic thyrotropin-releasing factor (TRF) administered iv induced a significant rise within 5 min in the concentration of plasma prolactin and plasma TSH in 13 children with constitutional short stature (Group I), 13 patients with isolated growth hormone deficiency (Group II), and in 13 patients with idiopathic hypopituitary dwarfism, including TSH deficiency (Group III). The mean peak concentration of plasma prolactin was 25.2 ng/ml for Group I, 27.7 ng/ml for Group II, and 20.9 ng/ml for Group III. These values were not significantly different from one group to another. The mean peak concentration of plasma TSH was 20.7 μU/ml for Group I, 19.1 μU/ml for Group II, and 26.0 μU/ml for Group III. One patient with multiple pituitary hormone deficiencies had no detectable TSH rise (<1.5 μU/ml) following TRF, but had a normal rise in plasma prolactin of 20 ng/ml. The TRF stimulation test provides a means to distinguish primary from secondary hypopituitarism. These data provide further evidence that most patients with idiopathic hypopituitarism have a primary deficiency of one or more hypophysiotropic hormones.