|Budget Amount *help
¥2,000,000 (Direct Cost : ¥2,000,000)
Fiscal Year 1995 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1994 : ¥1,100,000 (Direct Cost : ¥1,100,000)
1. In the in vitro perfused rebbit ovaries, (1) growth hormone may amplify gonadotropin actions in the process of follicular development and ovulation by stimulating ovarian insulin-like growth factor-I production, and (2) gonadotropin stimulates renin-like activity and angiotensin II production in the ovary, suggesting that ovarian renin-angiotensin system may play an important role in the process of oocyte maturation after exposure to gonadotropin.
2. The effects of GnRHa administration on follicular development and atresia were evaluated in the women undergoing ovarian stimulation with hMG and/or GnRHa for the purpose of in vitro fertilization.
(1) The significantly higher number of aspirated follicles and the similar levels of serum estradiol in the GnRHa/hMG cycles compared with the hMG-only cycles suggests the suppression of steroidogenesis in the GnRHa treated cycles.
(2) Although serum concentrations of LH did not differ significantly between the two treatment regimens in the earl
y and mid follicular phase, GnRHa administration significantly suppressed LH secretion in the late follicular phase. In response to gonadotropin stimulation, a continuous rise serum androstenedione was observed in the both treatment cycles. The above normal concentrations of androstenedione on the day of hCG administration, which indicate the atretic change of the follicles, were associated with low fertilization and cleavage rates. In the GnRHa/hMG cycles, the serum concentrations of androstenedione were significantly lower and the number of fertilized oocytes was significantly higher than in the hMG-only cycles, thus reflecting high viability of the follicles. These data suggest that higher number of recruited follicles maintain viability and mature in the GnRHa treatment cycles.at least in part, by suppressing LH secretion in the late follicular phase.
The present studies demonstrate that not only gonadotropins but also local factors in the ovary may play important roles in the process of follicular development and atresia.