Effect of psychological stress on human growth hormone response to thyrotropin-releasing hormone in normal controls

Human growth hormone (hGH) responses to thyrotropin-releasing hormone (TRH) were investigated in normal subjects under psychological stress. Fifteen subjects (4 men and 11 women), whose ages ranged from 19 to 22 years, were studied. The mirror-drawing test (MDT) was performed to induce psychological stress. Plasma hGH and prolactin (PRL) were determined serially before, during and after the following tests: TRH alone (500 micrograms synthetic TRH i.v. bolus), MDT alone, and TRH with MDT. The changes in hGH concentrations with MDT alone were not significant. The hGH response to TRH alone also showed no remarkable change; however, hGH responses to TRH combined with MDT were significantly higher than the responses to TRH alone. PRL did not respond with MDT alone but responded significantly with the other two tests. Thus there was a divergence in hGH and PRL secretion to TRH and psychological stress. Significant increases in hGH secretion were observed only when TRH and psychological stress were combined as stimuli.