Plasma vasopressin during normal menstrual cycle.

Plasma vasopressin concentrations were measured on days 5-7, 11-13, 15-17 and 21-23 of the normal menstrual cycle in 14 healthy women. The four determinations of vasopressin concentrations did not differ significantly. Plasma vasopressin showed, however, a tendency to increase on days 11-13, when the peak concentration of serum estradiol occurs. After the ovulation a decreasing tendency was seen. There was no significant correlation between circulating vasopressin and 17 beta-estradiol studied in four stages of the menstrual cycle.