The objective of this study was to evaluate the effect of GnRH or estradiol in a CIDR-based timed Al (TAI) protocol on follicular turnover, synchronized ovulation and pregnancy rates in Holstein cows. Cows were treated at random stages of the estrus cycle with an insertion of an intravigal progesterone (1.9 g) device (CIDR, Day 0) and either no other treatment (control group; n=10), injection of 100 ug fertirelin acetate (GnRH group; n=10) or 4 mg estradiol benzoate (estradiol group; n=10). Seven days later devices were removed and an injection of 25 mg PGF2a was administered. On Day 9, 100 ug GnRH was administered. Cows received a fixed-time insemination 16 h after injection of the GnRH.

높은 농도로 투여된 성선자극호르몬 분비호르몬 이성체(GnRH-Ag)는 성선자극호르몬의 분비를 억제시키고 난소의 기능을 억제하는 하는 것으로 보고되고 있다. 그러나 체외수정 및 배아이식 시술과정에서 과배란 유도를 위해 다량의 GnRH-Ag를 사용하고 있으며, 이는 progesterone을 보충해 주어야 하는 황체기 결함을 유발시킨다. 본 실험의 목적은 이러한 황체기 결함을 유발시키는 원인을 알아보고자 사람 과배란 유도 과정과 비슷하게 생쥐에 GnRH-Ag

성선자극호르몬 분비호르몬은 시상하부에서 분비되며, 포유동물의 생식에 중추적인 역할을 담당한다. 골든 햄스터는 계절적으로 번식하는 포유동물이며, 생식 활동은 광주기(하루 중 낮의 길이)에 의해 결정된다. 장주기(12.5 시간 이상의 빛)는 생식 능력을 유지시키지만, 단주기(12시간 이하의 빛)는 생식 기능을 억제한다. 성선자극호르몬 분비호르몬과 광주기의 상호 관계를 자세히 조사하기 위하여 랫트 성선자극호르몬 분비호르몬 cDNA를 포함하는 벡터를 여러 농도

GnRH는 10개의 아미노산으로 구성된 호르몬으로서 생식기능을 조절, 관장하는 중요한 역할을 담당하는 것으로 알려져 있다. 특히 임신 중에는 태반에서 hCG의 분비를 조절하는 중요한 역할을 한다. 최근 사람의 두 번째 GnRH 유전자가 발견되었으며 그 10개의 아미노산 서열은 닭에서 두 번째로 발견된 GnRH (chicken GnRH-II)와 동일한 것으로 확인되었다. 이제까지 사람에서의 두 번째 GnRH (GnRH-II)의 발현은 중뇌와 신장에서 보고

The hypothalamic peptide GnRH plays a central role in the regulation of the mammalian reproductive axis. Recent studies suggested that GnRH stimulates or inhibits the ovarian steroidogenesis and gametogenesis directly. Our previous report indicated that GnRH gene is expressed in adult rat ovary as well as in hypothalamus and that the expressed GnRH may induce the follicular atresia and apoptosis of ovarian granulosa cells in rat. Therfore, we studied whether GnRH gene is expressed in the mouse fetal ovary, when the germ cells are degenerating by apoptosis during gonad diffeerentiation. Mouse fetal gonads were obtained on the 12, 15,18 and 20th day of gestation from the mother mice superovulated (10 IU PMSG and 10 IU hCG) and mated. The morphological changes of fetal ovaries were examined histochemically by hematoxylin-eosin staining. The fetal sex was confirmed by PCR methods for sexing. RT-PCR methods were used to examine the expression of GnRH gene and the sex steroid hormones were determined by conventional radioimmunoassays. The levels of estradiol (E) and progesterone (P) were increaseduntil 18th day of gestation and then E was decreased just before parturition. The morphological changes of fetal gonadal tissue sections showed the ovarian development and coincided with the result of PCR analysis for sexing using ovary- or testis- specific oligonucleotide primers. Immunoreactive GnRH in placenta was decreased gradually until the end of gestation but fetal brain and ovarian GnRH were increased. The level of GnRH gene expression was increased during fetal ovarian development from 12 till 18th day and decreased suddenly on 20th day just before birth. From these results, it is suggested that ovarian GnRh may play a regulatory role on the germ cell differentiation of fetal ovary.