Cortisol, estradiol-17β, and progesterone secretion within the first hour after awakening in women with regular menstrual cycles

Cortisol concentration in both serum and saliva sharply increases and reaches a peak within the first hour after waking in the morning. This phenomenon is known as the cortisol awakening response (CAR) and is used as an index of hypothalamus-pituitary-adrenal (HPA) axis function. We examined whether ovarian steroid concentrations increased after awakening as with the CAR in the HPA axis. To do this, cortisol, estradiol-17β (E(2)), and progesterone (P(4)) concentrations were determined in saliva samples collected immediately upon awakening and 30 and 60 min after awakening in women with regular menstrual cycles and postmenopausal women. We found that both E(2) and P(4) concentrations increased during the post-awakening period in women with regular menstrual cycles, but these phenomena were not seen in any postmenopausal women. The area under the E(2) and P(4) curve from the time interval immediately after awakening to 60 min after awakening (i.e. E(2)auc and P(4)auc) in women with regular menstrual cycles were greater than those in the postmenopausal women. E(2) and P(4) secretory activity during the post-awakening period was influenced by the phase of the menstrual cycle. E(2)auc in the peri-ovulatory phase and P(4)auc in the early to mid-luteal phase were greater than in the menstrual phase. Meanwhile, cortisol secretory activity during the post-awakening period was not influenced by menstrual status or the phase of menstrual cycle. These findings indicate that, as with the CAR in the HPA axis function, ovarian steroidogenic activity increased after awakening and is closely associated with menstrual status and phase of menstrual cycle.