LHRH and steroid levels in normal ovulatory women

Synthetic LHRH was given intravenously in a dose of 250 μg to a group of 7 normal women in different phases of the menstrual cycle. The LH response was more pronounced in the preovulatory and luteal phase than in the follicular phase of the cycle. The FSH response was less than that of LH and was the same in all phases of the cycle. No significant changes were observed in the plasma levels of estradiol 17β, progesterone, or testosterone for up to 6 hr as well as 24 hr after LHRH administration in any of the subjects studied. In 2 of 3 subjects, administration of LHRH in the luteal phase resulted in the prolongation of the cycle. No effect on cycle length was observed when LHRH was given at other times of the cycle. LHRH did not affect the length of the subsequent cycle regardless of the day of administration.