Thyroid hormones and TSH, prolactin and LH responses to repeated TRH and LRH injections in depressed patients

Abstract

Patients (12) with unipolar depressive disorders received 600 .mu.g of synthetic thyroid hormone releasing hormone [TRH] or luteinizing hormone releasing hormone [LRH], in a random order, for 3 days each. Placebo injections were given as two 3-day courses prior to and between the active treatments. Serum thyroid stimulating hormone [TSH], prolactin (Prl) and luteinizing hormone [LH] were measured by radioimmunoassays prior to the experiment and immediately before and 20 min after each injection. Serum thyroxine [T4] and triiodothyronine [T3] were determined by radioimmunoassays before the treatments and 24 h after the 1st 2-TRH injections. Serum T4 level in depressed patients did not differ from controls. Serum T3 level in depressed patients was significantly below, and the reverse T3 [rT3] level was above the normal mean. The latter difference was not statistically significant due to the large variation of rT3 levels among the depressed patients. The TSH responses did not differ from controls after the 1st injection but the responses after the 2nd injection were lower than in a control study. The Prl responses to TRH were subnormal in 7 out of 8 patients. Blunted LH responses to LRH were seen in 3 patients.