TY - JOUR
T1 - Effect of 17β-estradiol on hypothalamic GnRH-II gene expression in the female rhesus macaque
AU - Densmore, V. S.
AU - Urbanski, H. F.
PY - 2004/8
Y1 - 2004/8
N2 - The hypothalamus of rhesus macaques expresses two molecular forms of gonadotropin-releasing hormone (GnRH-I and GnRH-II). However, it is unclear whether these two neuropeptides play similar roles in the control of reproductive neuroendocrine function, especially in the context of positive and negative estrogen feedback. To address this issue, in situ hybridization histochemistry was used to compare the effect of 17β-estradiol (E) on the expression of GnRH-I and GnRH-II mRNA in the medial basal hypothalamus (MBH) of adult female macaques. GnRH-I mRNA expression was found to be significantly (P<0·01) more abundant in ovariectomized (ovx) animals compared with ovariectomized E-treated (ovx+E) animals. In marked contrast, GnRH-II mRNA expression was found to be significantly (P<0·05) more abundant in ovx+E animals than in the ovx animals. To help elucidate how E exerts this stimulatory action on GnRH-II gene expression, hypothalamic sections were subsequently double labeled using a combination of immunohistochemisty for estrogen receptor (ER) -α or -β and in situ hybridization histochemistry for GnRH-II. Approximately 50% of the GnRH-II positive cells in the MBH were found to express ERβ, but none expressed ERα. Taken together, these data give credence to a novel pathway by which E may control the primate neuroendocrine reproductive axis, one that involves stimulation of GnRH-II release via an ERβ-mediated mechanism.
AB - The hypothalamus of rhesus macaques expresses two molecular forms of gonadotropin-releasing hormone (GnRH-I and GnRH-II). However, it is unclear whether these two neuropeptides play similar roles in the control of reproductive neuroendocrine function, especially in the context of positive and negative estrogen feedback. To address this issue, in situ hybridization histochemistry was used to compare the effect of 17β-estradiol (E) on the expression of GnRH-I and GnRH-II mRNA in the medial basal hypothalamus (MBH) of adult female macaques. GnRH-I mRNA expression was found to be significantly (P<0·01) more abundant in ovariectomized (ovx) animals compared with ovariectomized E-treated (ovx+E) animals. In marked contrast, GnRH-II mRNA expression was found to be significantly (P<0·05) more abundant in ovx+E animals than in the ovx animals. To help elucidate how E exerts this stimulatory action on GnRH-II gene expression, hypothalamic sections were subsequently double labeled using a combination of immunohistochemisty for estrogen receptor (ER) -α or -β and in situ hybridization histochemistry for GnRH-II. Approximately 50% of the GnRH-II positive cells in the MBH were found to express ERβ, but none expressed ERα. Taken together, these data give credence to a novel pathway by which E may control the primate neuroendocrine reproductive axis, one that involves stimulation of GnRH-II release via an ERβ-mediated mechanism.
UR - http://www.scopus.com/inward/record.url?scp=4444256602&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=4444256602&partnerID=8YFLogxK
U2 - 10.1677/jme.0.0330145
DO - 10.1677/jme.0.0330145
M3 - Article
C2 - 15291749
AN - SCOPUS:4444256602
SN - 0952-5041
VL - 33
SP - 145
EP - 153
JO - Journal of molecular endocrinology
JF - Journal of molecular endocrinology
IS - 1
ER -