J Korean Soc Endocrinol.  1997 Dec;12(4):518-527.

Regulation of Estrogen Receptor mRNA in Rat Anterior Pituitary Gland

• Chun MS
• Park DB
• Park YB
• Kam KY
• Kim CM
• Yoo KJ

Abstract

The estrogen receptor (ER) is present in a wide variety of mammalian tissues and is required for the physiological responses of estrogen, including estrogen-induced tissue-specific changes in gene expression. But most of our knowledge on the regulation of ER mRNA levels comes from in vivo steroid replacement experiments or cancer cell lines that express the ER. Thus the present study was attempted to determine 1) the anterior pituitary ER mRNA levels during rat estrous cycle 2) if estradiol itself directly modulates the ER mRNA levels in cultured rat anterior pituitary using RT-PCR method. In rats with 4 day estrous cycle, the ER mRNA levels in anterior pituitary gland reached to maximum at proestrus 11:00h just before serum estradiol concentration showed the highest. From then, the ER mRNA levels gradually declined during the rest of the proestrus. On the other hands, in cultured rat anterior pituitary cells, the ER mRNA levels were significantly decreased by the treatment of estradiol. These results indicate that the surge of estradiol was proceeded by the increase in pituitary ER mRNA levels during the proestrus and in cultured anterior pituitary cells, estrogen might be involved in the down-regulation of the ER mRNA levels.

MeSH Terms

Animals
Cell Line
Down-Regulation
Estradiol
Estrogens*
Estrous Cycle
Gene Expression
Hand
Pituitary Gland, Anterior*
Proestrus
Rats*
RNA, Messenger*
Estradiol
Estrogens
RNA, Messenger