Variations of neurohypophysial function in normally cycling women.

Using a neurophysin radioimmunoassay, we have studied basal neurohypophysial function in seven normal women. An increase in neurophysin blood levels has been demonstrated during the ovulatory and/or luteal phase as compared to the follicular phase; these variations are related to the changes in the circulating levels of 17beta-estradiol. The data provide additional evidence for a relationship between estrogens and neurohyprophysial function, as previously shown following exogenous administration of estriol and ethinyl estradiol in man.