Effect of day-to-day variations in adrenal cortex hormone levels on abdominal symptoms

Eleven college students (4 males and 7 females) participated in this study. The participants were asked to collect their saliva immediately after awakening and before bedtime for eight consecutive days. They also completed a questionnaire about abdominal symptoms before bedtime. The linear mixed model was applied to analyze the effects of the day-by-day variability or the 8-day average adrenal hormone level (at awakening, before bedtime, slope from awakening to bedtime) on abdominal symptoms.The day-to-day variability of cortisol levels before bedtime was negatively related with loose stool, while the day-to-day variability of the cortisol slope was positively correlated with loose stool. A low 8-day average dehydroepiandrosterone-sulfate level at awakening was positively related with frequent bowel movements, loose stool, and long bouts of severe abdominal pain. Likewise, a low 8-day average dehydroepiandrosterone-sulfate slope was positively related with long bouts of abdominal pain.Low cortisol levels before bedtime and a steeper diurnal cortisol slope during the day may be related to bouts of diarrhea during the day.The effect of changes in the hypothalamic-pituitary-adrenal (HPA) axis on abdominal symptoms has been previously reported. On the basis of the results of previous studies, Mayer et al. (2002) suggested that complex interrelationships exist between gut-associated immune tissue, the central nervous system, and the enteric nervous system [1]. Psychosocial stressors activate stress circuits within the emotional motor system, and the resulting peripheral output is manifested in the form of cortisol, corticotrophin-releasing factor, and autonomic (norepinephrine and epinephrine) responses, which induces the mucosal immune system to activate a Th2 response [2,3]. An increase in mast cells brought about by alterations in the Th1/Th2 balance may stimulate bowel movements by altering the access of luminal organisms and antigens to the gut immune system [4,5].P