|
KMID : 0578319940040010039
|
|
Molecules and Cells
1994 Volume.4 No. 1 p.39 ~ p.44
|
|
|
Temporal Changes in Ovarian Gonadotropin-releasing Hormone mRNA Levles by Gonadotropins in the Rat
|
|
Lee, Sung Ho
Song, Eun-Seob/Yu, Sun kyeong/Kim, Changmee/Lee, Dae Kee/Choi, Wan Sung/Kim, Kyungjin
|
|
|
Abstract
|
|
|
The present study examines whether gonadotropins are involved in the regulation of ovarian GnRH gene expression and how ovarian GnRH gene expression temporally correlates with alterations in hypothalamic GnRH, pituitary LH1, gene expression in response to gonadotropins. Hypothalamic and ovarian GnRH mRNA and pituitary LH1, mRNA levels were determined by respective RNA-blot hybridizations, and ovarian GnRH and estradiol contents and serum LH levels were measured by respective radioimmunoassays. Three animal models such as 1) PMSG-treated, 2) PMSG and hC(;-treated immature rats and 3) proestrous stage of adult rats were used. Immature rats (25-days old) were administered with PMSG (10 iu) at 10:00 h and 48 h later with hCG (10 iu) to induce ovulation. In the PMSG-injected model, hypothalamic GnRH mRNA levels were markedly augmented about 9-fold at 50 h, and pituitary LH mRNA 3-fold at 52 h after PMSG administration. Serum LH levels were increased to the preovulatory surge levels at 56 h, and ovarian GnRH mRNA levels were augmented 4-fold at 60 h after PMSG injection. Administration of hCG also induced a marked enhancement in ovarian GnRH mRNA levels in comparison to the values shown in both intact and PMSG-treated rats at 52 h and 54 h, respectively. In the proestrous stage of normal adult rats, pituitary L.H1, mRNA levels were peaked at 16:00 h. The preovulatory LH surge %vas evident at 4 h before increment in ovarian GnRH mRNA levels as shown in PMSGtreated rats. The present study clearly showed the sequential increase in hypothalamic GnRH rill pituitary LH1, mRNA and ovarian GnRH mRNA levels, indicating that ovarian GnRH may plav
a possible role in the control of follicular maturation and the ovulation process.
|
|
|
KEYWORD
|
|
|
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
  
|
|