Changes of sex steroids and prostaglandins around induced ovulation
1997
Yamada, Y. (Hokkaido National Agricultural Experiment Station, Sapporo (Japan)) | Kawai, Y.
The present study was conducted to clarify the changes of sex steroids and prostaglandins around induced ovulation in the prepuberal gilts. Forty eight prepubertal gilts were injected intramuscularly will hCG (6 IU/kg of body weight; kg.b.w.) 72 hours after receiving PMSG (12 IU/kg.b.w.). Ovulation was verified by laparotomy. Changes in concentrations of steroids and Prostaglandins in peripheralblood plasma, ovarian vein blood plasma and follicular fluid were examined. Ovulation rate was 0% until 24 hours after hCG injection and 16, 60, 80, 86, 85% at 32, 36, 42, 72 hours after hCG injection, respectively. And it is suggested that ovulation occurred 32 to 48 hours after hCG injection. Regarding the levels of sex steroids in the pheripheral blood plasma, ovarian vein blood plasma and follicular fluid, estradiol-17beta and testosterone levels decreased as the time of ovulation approached. Progesterone levels increased markedly after ovulation. PGF(2alpha) levels in the ovarian vein blood plasma increased near the time of ovulation. Furthermore, the levels of PGF1, PGF(2alpha) and 6-keto-PGF(1alpha) in the follicular fluid also increased rapidly near the time of ovulation. Based on these results, it is suggested that PGs are produced in the ovaries as the time of ovulation approaches and that PGs have some roles on ovulation
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