Medroxy-pogesterone acetate(MPA)가 생쥐에서 성적행동, 배란 및 자궁상태에 미치는 영향에 대하여 실험한 바 다음과 같은 결론을 얻었다. 1. 교미전에 MPA(2㎎/㎖)를 주사하면 발정일을 제외한 발정주기 기간중 어떠한 날에 도 교미를 억제한다. 2. MPA(2㎎/㎖)는 Pregnant Mare’s Serum(PMS) 2 iu과 Human Chorionic Gonadotrophin(HCG) 2 iu으로 유도된 인공배란에는 영향을 미치지 안었다. 3. MPS는 자궁상태에 심한 이상을 나타내었다. 4. 이와 같은 MPA의 작용과 PMS나 HCG의 중량에는 상호 상관관계를 가할 수 없었 다. 이상의 실험결과로 미루어 보아 생쥐에서 MPA는 배란에 대한 영향은 없었으나 교미 와 자궁상태에는 강한 영향을 나타내었으며 이러한 효과는 MPA가 주로 시상하부와 뇌 하수체를 연결하는 tract에 작용하고 또 한 난소에도 작용하여 나타나는 것으로 사료된다.

Females of most mammals, except for higher primates, show specific sexual behavior and permit copulation only during estrus when ovulation occurs, During this period females reveal peculiar sexual behavior while males, seizing opportunities for copulation from such behavior, usually carry out copulation (Nalbandov,1958). Among the mammals, rats and mice, for instance reveal the fohowing three signs of sexual begavior during estrus; first, permission of copulation; second, lordosis and male like mounting; and third, running activity (Young, 1961). Ho-wever these signs of sexual behavior come always during estrus, and females allow copulation with males only during that period. In the early stage of reproductive physiology, it was confirmed through research that sexual behavior during estrus directly linked with ovaries are removed( Ball, 1936; Robson, 1938; Young and Orbisin, 1944). Later research by many investigators led to discovery of the fact that an appropriate combination of estrogen and progesterone os required to induce sezual behavior in the rat ( Boling and Blandau, 1939; Beach,1942), mouse(ring, 1944), hamster (Frank and Fraps, 1945` Kent and Lieberman,1947) and cow (Melampyet al., 1957). Zeilmaker (1966) observed that progesterone had the effect of advance or delay in the release of gonadotrophic hormones under the influence of time of injection and estrous cycle of the rat. Progesterone had also been described to have a biphasic effect on estrous behavior and pituitary stimulation are mediated by means of altered thresholds of neural activity (Kawakami and Sawyer,1959). The synthesis of steroid hormones has become possible, while medroxy-progesterone acteate (MPA), which has a far stronger biological effect than progesterone, has emerged as a contraceptive drug (Zanartu, 1968, Soichet, 1967). MPA is believed to have contraceptive effects by inhibition of ovulation (Mishell, 1967; Zanartu etal., 1970) and by influencing the uterine cervical mucus and endonetrium (Mishellet al., 1968; Zanartu et al., 19970). In rats, MPA is known to inhibit ovulationuterine water retention and vaginal epithelial cornification(Banik and Herr, 1969). MPA is also believed to delay or suppress implantation in rats (Barnes and Meyer,1964; Yoshinaga and Greep, 1971), but not in mice (Chung, 1977). It was therefore the aim of this study to research the effect of MPA on the sexual behavior of mice and to ascertain the relation between ovulation and sexual behavior after ovulation has been induced with gonadotrophin injection. Mammals used for the experiment were mice weighing about 25 to 30 grams, while the mammal subjects were adapted to an environment where illumination was controlled in order to keep the estrous cycle constant. Bright and datk conditions were maintained to last 14 and 10 hours, respectively, while the indoor thmperature was kept at 17 to 25 degrees C. The progesterone used for this experiment was MPA (2mg/ml) manufactured by Upjihn pharmaceutical Co. In order to ensure synchronization with the estrous cycle, 2 international unit (ju0 of pregnant mare`s serum (PMS) was injected into the intraperitoneal cavity, and after the elapse of 48 hours, 2ju of human chorionic gonadotrophin (HCG) was also injected into the intraperitoneal cavity, and then the female mouse was put into a cage along with mature male, The next morning copulation was confirmed by using vaginal plugs. In addition, in order to observe ovulation, the number of ovulated eggs and the state of uterine condition, the mice were slaughtered through cervical dislocation, and the fallopian tube was removed by opening the abdominal cavity. Then the number of eggs collected by washing the fallopian tube from the upper part down with 0.85% physiological salt water was counted under a dissection microscope.