Physicians' daily work is accompanied by emotional and physical stress, and 24-h shifts are considered to be a major stressor. Effects of stressors on the hypothalamic-pituitary-adrenal (HPA) axis can be evaluated by estimating the glucocorticoid excretion in urine samples. We characterized the impact of a 24-h working period on the urinary glucocorticoid excretion of physicians and focused on gender differences. 10 females and 12 male physicians collected 24-h urine samples during a 24-h shift ("on-duty") and on a free weekend ("off-duty") that were analyzed by gas chromatography-mass spectrometry. Urinary glucocorticoid excretion rates (GERs) were assessed by addition of the 24-h excretion rates per square meter body surface area for the seven major urinary cortisol and cortisone metabolites. Women showed generally lower glucorticoid excretion rates compared to men. Only male physicians had increased GERs on duty compared to off duty. As a measure of change between being on duty and off duty, the ratio GERs on duty/GERs off duty was significantly higher in males than in females. Thus, the 24-h shift stress factor generates diverging results between female and male subjects with activation of the HPA axis primarily in male physicians.
Keywords: gas chromatography–mass spectrometry; gender; glucocorticoid excretion; hypothalamic–pituitary–adrenal axis; physicians; response to stressors; urinary steroid metabolomics.