Failure of positive feedback of oestradiol during chronic intranasal luteinizing hormone-releasing hormone agonist treatment.

An oestrogen provocation test was performed in five healthy women during chronic intranasal treatment with 400 or 600 micrograms of the superactive LHRH agonist D-Ser(TBU)6-EA10-LHRH daily. Oestradiol benzoate 2.5 mg was administered intramuscularly after at least 3 months of LHRH agonist treatment. The serum levels of FSH and LH were not affected by the oestrogen injection. Failure of positive feedback of oestradiol may be one explanation for the inhibition of ovulation which occurs during chronic LHRH agonist treatment.