Prolactin and TSH responses to TRH, chlorpromazine and L-dopa in children with human growth hormone deficiency.

Prolactin (PRL) and TSH responses to TRH, chlorpromazine (CPZ) and L-DOPA were studied in 23 children (15 male and 8 female) with human growth hormone (HGH) deficiency. Eight patients (group I) showed normal PRL response to TRH and CPZ but TSH response to TRH was delayed in 4 of this group. Twelve patients (group II) had normal (4 patients) or higher (8 patients) baseline PRL level and showed lower PRL response to CPZ than that to TRH. TSH response to TRH was normal in 3, blunted in 1, and delayed in 8 patients. Three patients (group III) had no PRL response to either TRH or CPZ. TSH response to TRH was normal in 1 but blunted in 2 patients. Of 8 patients with a higher baseline PRL level (group II and III), L-DOPA suppressed PRL secretion to less than 50% of the initial value in 7 patients, but not in 1 patient, in whom the diagnosis of hypothalamic tumour was established on brain surgery following these examinations. These results suggest that hypothalamic disorders are involved in more than half of 23 children with HGH deficiency.