Parallel changes of the responses of thyrotropin, growth hormone and prolactin to thyrotropin-releasing hormone in endogenous depression

The responses of growth hormone (GH) and prolactin (Prl) to thyrotropin releasing hormone (TRH) were studied in two selected groups of patients with endogenous depression (ED). One group, ED 1, was characterized by an increased thyrotropin (TSH) response to TRH after recovery from depression and by a good prognosis, whereas the other group, ED 2, was characterized by an unaltered TSH response and relapse within six months after stopping the antidepressive treatment. (1) After treatment significantly increased responses of GH (p <0.01) and Prl (p <0.05) to TRH were found in group ED 1, whereas those in group ED 2 were unchanged. (2) Using an increase of the GH response after treatment of 0.5 mg/ml compared to that before treatment, and an increase of 8.0 ng/ml of the Prl response, a correct prediction of the prognosis was possible in 74 and 72% of the patients, respectively. Using the TSH response to TRH we have previously reported correct prediction in 91% of patients with ED. This value is significantly higher than those obtained with the GH and Prl responses (p <0.05). (3) GH and Prl responses in ED were compared to those obtained in healthy and psychiatric controls, but they were found to be of no diagnostic value.