Differences between diurnal patterns of salivary cortisol and dehydroepiandrosterone in healthy female adolescents

The adrenal hormones cortisol and dehydroepiandrosterone (DHEA) share a common secretagogue: adrenocorticotropic hormone; however, secretion of these hormones can be dissociated suggesting subtle individual regulation at the level of the adrenal gland. We examined differences in the diurnal patterns of cortisol and DHEA secretion in healthy adolescent girls, with the aim of informing the possibility of exploiting these differences to aid interpretation of data from clinical populations in which these patterns can become dysregulated. Fifty-six healthy females aged 10-18 years provided saliva samples at 0 and 30 min (morning samples) and 12 h post-awakening on 2 consecutive weekdays. For morning salivary cortisol in relation to morning DHEA concentrations, correlational analysis revealed only a trend (p = 0.054). Similarly, the association between evening cortisol and DHEA was characterised as a trend (p = 0.084). Mean morning DHEA concentrations showed more day-to-day consistency than equivalent cortisol samples (r = 0.829 for DHEA and 0.468 for cortisol; z = 3.487, p < 0.0005). Unlike the cortisol pattern, characterised by a marked awakening response (cortisol awakening response, CAR), a significant rise in DHEA concentration post-awakening was not evident. Finally, there was a strong association between morning and evening concentrations of DHEA, not found for cortisol. The study shows differences in cortisol and DHEA secretion in the post-awakening period and informs work that seeks to examine correlates of dysregulated hypothalamic-pituitary-adrenal axis function. Parallel examination of both hormones enables enhanced interpretation of aberrant patterns of the CAR, i.e. an exploration of whether dysregulation affects both hormones (reflecting overall steroidogenic capacity) or cortisol alone (CAR-specific mechanisms).