Hypothalamic-pituitary functions in patients with idiopathic pituitary dwarfism. Further evidence for...

Somatotropic, thyrotropic, gonadotropic and corticotropic functions in 10 patients with idiopathic hypopituitary dwarfism (IH) were investigated. The patients were divided into two groups: Group I (5 patients) had normal plasma T4 levels, and Group II (5 patients) had T4 levels of less than 4.6 microgram/dl. In Group I three cases had isolated growth hormone (GH) deficiency and two cases had GH and gonadotropin (Gn) deficiencies; in Group II the 5 cases showed multiple anterior pituitary hormone deficiencies. In Group II, the plasma thyroid stimulating hormone (TSH) was 4.1-9.4 muU/ml and the response to thyrotropin releasing hormone (TRH) was greatly delayed and prolonged, with a maximum after 120 min instead of 15 min. The basal prolactin (PRL) level in Group II was 12-31 ng/ml, which was significantly higher than normal (P less than 0.001). In 4 cases in Group II, the plasma cortisol level increased 120 min after the infusion of lysine-vasopressin, whereas oral administration of metyrapone and hypoglycemia induced by insulin did not increase the plasma cortisol levels. From these findings it is concluded that hypothalamic lesions caused the pituitary hormone deficiencies in 4 Group II cases, and Group I may tentatively be differentiated from Group II by T4 determinations.