Pattern of plasma ACTH, hGH, and cortisol during menstrual cycle.

The pattern of secretion of plasma ACTH, hGH, TSH, LH, FSH and cortisol was studied in 12 menstrual cycles, representing 5 normal volunteers. Results were plotted by taking the LH-FSH midcycle peak as day 0. The typical menstrual cyclic LH and FSH pattern was observed in each case. ACTH, cortisol and hGH varied significantly throughout the menstrual cycle. ACTH was characterized by a decrease during the follicular phase, a nadir at day -2, followed by a significant increase to a peak at day 0, then a subsequent decrease and constant levels during the luteal phase until day +8. Cortisol was lowest in the follicular phase until day -4, and highest from day -2 to day 0. During the luteal phase, cortisol remained constant but was significantly higher than in the follicular phase (days -7 to -4). hGH showed a significant increase during the periovulatory period (days -3 to +3). No significant changes of plasma TSH were observed. These results suggest that pituitary hormones other than gonadotropins may be involved in the ovulatory mechanism, and reveal a degree of stimulation of the pituitary-adrenal axis without establishing whether the effect is direct or indirect.