Superovulation induction with exogenous gonadotropins

such as pregnant mare serum gonadotropin (PMSG) and human menopausal gonadotropin (hMG) is a well-established practical technique. The purpose of this technique is to achieve enhanced commercial production of genetically meritorious individuals in the livestock industry, to retrieve a number of oocytes and early embryos in various research fields including genetic engineering, and to treat medically diverse types of female infertility in human. In spite of these advantages, the results obtained from its application on large domestic and small laboratory animals generally appear very disappointing. In immature rats, administration of superovulatory doses of PMSG leads to a great reduction in fertilization rates, a substantial loss and degeneration of preimplantation embryos, and a partial or complete failure of implantation. Major defects following superovulatory treatment with PMSG could occur in the process of follicular development and oocyte maturation by hyperstimulation of PMSG on ovarian tissues because of prolonged biochemical action of PMSG that has long half-life. Hyperstimulation of PMSG on ovarian tissues also induced atypical ovulation of abnormal follicles that would not ovulate and regress under a regular estrous cycle. However, the precise mechanisms of these negative aspects exerted by superovulatory treatment are not fully understood. Ginseng has been regarded as one of the important remedies in oriental medicine for one thousand years. A review of classical oriental medicine literature showed that ginseng improves the functions of almost all the organs in the body, including reproductive organs. It has been sound that the most effective components in ginseng are saponins including ginsenosides which are plant glycosides having a triterpenoid dammarane skeleton as an aglycone, with three sites called R1, R2 and R3 for ester bonding with the glycones : glucose, rhamnose, xylose and arabinose. The specific structure of ginsenosides, a triterpenoid dammarane skeleton, is quite similar to that of ovarian steroid hormones, namely, cyclopentanoperhydrophenanthrene nucleus, implying that ginsenosides are biochemically active substances and that they act as functional ligands in steroid related reproductive organs. Recently, the action mechanisms of various ginsenoside fractions have been elucidated in many laboratories. For example, the fractions ginsenoside-Rg1, -Rh1 and -Rh2 exert, via glucocorticoid receptor, their biological actions which are to have glucocorticoid-response gene expressed, and/or to stimulate specific cell differentiation. However, there is scarcely any available data on the effects of ginseng components on the male or female reproductive system. It has been reported in clinical medicine that in mildly infertile men Korean ginseng components stimulated spermatogenesis and enhanced spermatozoa motility. In addition, in menopausal sterile women, the ingestion of Korean ginseng flour cured menopausal disorders by improving the ovarian function by increasing the blood supply into the ovary and raising serum 17b-estradiol level. In laboratory animals, there is only a single report on the ginseng effects on the male gonad. In adult male rats Korean ginseng saponin stimulated both the transportation of cholesterol to testicular cells and the biosynthesis of androgens from cholesterol in the testis. Therefore, the objective of this study was to investigate whether or not Korean ginseng saponins have a curative effect on ovarian dysfunctions caused by the administration of superovulatory doses of PMSG. In detail, this study examined the effects of Korean ginseng saponins on the ovulatory response, the morphological normalcy and nuclear maturation of ovulated oocytes, the ovarian weight and histology, and serum steroid hormone response at preand post-ovulatory phase in these rats.