Prolactin in patients with major depressive disorder and in healthy subjects. III. Investigation of basal and post-TRH prolactin during different forms of acute and chronic psychological stress.

Prolactin (PRL) levels after thyrotropin-releasing hormone (TRH) (delta PRL) were determined 4 times and basal prolactin levels 6 times in 10 healthy medical students before, during, and after a major examination in medicine. No significant differences in basal or delta PRL levels occurred during the examination period. Basal PRL was also measured in 14 doctors of medicine after delivering a paper at a clinical conference and a further 9 doctors both before and after delivering a paper. PRL was measured serially at 20-min intervals in 4 doctors on the day on which they presented the paper. No significant differences in PRL levels were found in any of the tests conducted during this kind of stress as compared with the corresponding values obtained under nonstressful conditions. Increases in PRL before delivering the paper were seen in 3 subjects, but such increases also occurred completely independently of stress. An 18-hr fast did not influence PRL secretion in 11 healthy volunteers. Both the information obtained from a review of the literature on the influence of stress on PRL secretion and our own results strongly suggest that contrary to common opinion, there is no evidence at all that psychological stress affects PRL secretion in man.