Plasma Immunoreactive T3, TSH and ACTH Before and After Provocative Tests in Idiopathic Hypopituitary Dwarfism

Abstract

The somatotropic, thyrotropic and corticotropic functions were investigated in 8 patients with idiopathic pituitary dwarfism. Particularly interesting were the results obtained from studies of the thyrotropic function. In the absence of clinical and conventional laboratory indices of hypothyroidism, measurement of plasma immunoreactive T3 and TSH before and after iv administration of 400 μg of TRH suggested the presence of borderline hypothyroidism. Basal plasma T3 values ranged from 20 to 55 ng/100 ml with a mean of 36.2 vs 55–160 ng/100 ml with a mean of 107. Moreover, plasma T3 response to TRH, although present, was markedly lower than in the controls (20–90 ng/100 ml with a mean of 62 vs 100–175 ng/100 ml with amean of 127). Plasma TSH response to TRH appeared markedly delayed and prolonged (maximal rise at 60 min instead of at 20 min). Also of interest were the results obtained from studies of the corticotropic function. The maximal plasma ACTH values after insulin-induced hypoglycemia was 91 + 17.5 ...