PATTERN OF OXYTOCIN CONCENTRATIONS IN THE PERIPHERAL-BLOOD OF HEALTHY WOMEN AND MEN - EFFECT OF THE MENSTRUAL-CYCLE AND SHORT-TERM FASTING

A sensitive and specific radioimmunoassay was used to measure basal oxytocin (OT) concentrations in samples of peripheral blood drawn q 10 min for 8 hrs from women during the follicular and luteal phases of the menstrual cycle and from men before and after 20 hrs of fasting. Few, if any, pulses of OT were found in the blood of men and women in this study. The pattern of OT concentrations in the circulation was the same during both stages of the menstrual cycle and was not affected by short-term fasting. The use of frequent sampling and the present assay system for OT did not detect a pulsatile pattern of OT concentrations in the blood of men and women in the basal state.