Effects of tricyclic antidepressants on human plasma levels of TSH, GH and prolactin.

Six healthy male volunteers were given chlorimipramine 25 mg t.i.d. or nortriptyline 25 mg t.i.d. in a randomized order of 7 days. Plasma samples were assayed for TSH, GH and prolactin before and after stimulation with TRH 200 microgram i.v. It was found that the tricyclic antidepressants did not exert any influence on plasma hormonal levels compared with no treatment conditions. Diminished TSH-responses following daily TRH injections were demonstrated in endogenously depressed and chronic schizophrenic patients. A decreased TSH-response was observed in healthy volunteers after a second TRH injection with an interval of 2 days between the TRH injections. A complete restoration of the TSH-response was obtained after an interval of 4 days.