Concentrations of estradiol (E₂), estrone (E₁), androstenedione (A), testosterone (T), progesterone (P) and luteinizing hormone (LH) in peripheral blood were measured simultaneously in the same samples taken at frequent intervals during 5 normal and 3 dexamethasone-treated (0.5 mg, 4 times daily) menstrual cycles. In the normal cycles, mean concentrations and patterns of LH, E₂, E₁ and P were similar to those previously reported. Although cyclic patterns of plasma T were less marked than A, mean concentrations were significantly higher at midcycle than at other times of the cycle. The plasma A levels demonstrated random daily fluctuation; however, a progressive increase in concentrations occurred during the follicular period (121 ± 27 ng/100 ml), reaching maximum concentrations (167 ± 34 ng/100 ml) during the midcycle period.

Dexamethasone treatment apparently did not affect ovulation and, although the luteal phase was of normal length, a prolongation of the follicular phase (18–21 days vs 13–16 days in the normal cycles) was seen. The patterns of all hormones studied were comparable to those seen in the normal cycles. While the mean concentrations of E₁, E₂, P and LH were not different from normal, those of plasma androgens were significantly lower during dexamethasone suppression; early follicular (36 ± 16 and 91 ± 32 ng/100 ml), midcycle (38 ± 9 and 124 ± 28 ng/100 ml) and midluteal (28 ± 11 and 73 ± 38 ng/100 ml) periods for T and A, respectively. The similarity of the patterns of T and A to that of estrogen and the persistence of a midcycle elevation in spite of adrenal suppression is suggestive of its origin from the ovary.