[Menstrual cycle stimulation in the in vitro fertilization program--effects on estrogen and progesterone receptors of...

Clomiphene in combination with human menopausal gonadotropin (HMG) or HMG alone was used for ovarian stimulation in the IVF program. In 41 cases without embryo transfer (ova could not be obtained or fertilised) 7-8 days after laparoscopy on endometrial biopsy was performed. Serum steroid hormone levels were estimated at the same day and in the time before follicular puncture. Histological classification of the received endometrium and the determination of the kinetic parameters of cytosolic estrogen and progesterone receptors were carried out. A strong correlation exists between histological results and receptor properties. Luteal phase defects are not only connected with a significant decrease of receptor binding capacity but also an increase of the dissociation constants occurs. Clomiphene HMG treatment results in general reduction of binding affinity of the cytosolic estrogen receptor. No correlation was found between the serum hormone levels at day of biopsy and the endometrial histology or receptor parameters on the other hand.