By assaying various urinary hormones, especially gonadotropin, it was investigated whether the rebound phenomenon of the human ovarian function can be regarded as belonging to a series of reactions of the hypophyseo-ovarian system.
1) After administration of Debout's pill of estrogen, Crook & Butt's GA and GB were determined. The results showed that these frac-tions were increased in the ovulatory and luteal phase of the rebound cycle. According to the biological assay, thg fractions tended to increased in the follicular and ovulatory phase.
2) Three spayed women were given 10 mg of benzesterol, and GA and GB were found remarkably increased over the pre-adminis-tration values, indicating the rebound phenomenon in gonadotropin.
3) Further, estrogen and 17-KS tended to increase in the rebound cycle, but no remarkable change in 170HCS.
4) There were no remarkable increase in GA and GB after administration of 19-norsteroid.