Regulation of amphiregulin, EGFR-like factor expression by hCG in cultured human granulosa cells.
BACKGROUND
It has long been suspected that the epidermal growth factor (EGF) receptor and some of its putative ligands may play an important role in ovarian function. Amphiregulin (AR) is the growth factor with an EGF-like motif, but its potential role in signalling in the ovary is still obscure. AR gene expression and its functional effect were evaluated in human granulosa cells from immature follicles.


METHODS
Granulosa cells from immature follicles with early menstrual phase were cultured with or without 200 mIU/ml of FSH stimulation, following with or without 1 IU/ml of hCG. mRNA levels of AR and luteinising hormone replacement (LHR) were semi-quantified using RT-PCR. Progesterone (P) concentration in the medium was assayed.


RESULTS
LHR mRNA was expressed 48 h after FSH stimulation without AR mRNA expression. AR mRNA was expressed 1 h after hCG stimulation, and increased the intensity in 6 h. P biosynthesis was increased by AR in a dose-dependent manner. AR mRNA was elevated by forskolin stimulation without FSH and hCG stimulation before LHR mRNA expression. When cultured with FSH for 15 h, followed by increasing doses of hCG stimulation for 6 h, the AR mRNA levels increased according to hCG concentration up to 1,000 mIU/ml.


CONCLUSIONS
Occurrence of LHR gene expression following FSH stimulation was necessary for the AR gene expression in vivo, and the AR gene was induced by forskolin without LHR gene expression in vitro. P biosynthesis was stimulated, to some extent, by AR. This result suggests the differentiation effect of AR on granulosa cells. AR might be a mediator of LH signals before ovulation.
Negishi
Hiroaki
H
Reproductive Centre, Women's Clinic Oizumigakuen, Tokyo, Japan. h-negishi@kiyosenomori.com
Negishi
H
H
Ikeda
Chiaki
C
Nagai
Yoko
Y
Satoh
Akiko
A
Kumasako
Yoko
Y
Makinoda
Satoru
S
Ustunomiya
Takafumi
T
D066258:Amphiregulin; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D066255:EGF Family of Proteins; D066246:ErbB Receptors / Q000096:biosynthesis* / Q000235:genetics; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D006023:Glycoproteins / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000096:biosynthesis* / Q000235:genetics; D011374:Progesterone / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
C587848:AREG protein, human; D066258:Amphiregulin; D006063:Chorionic Gonadotropin; D066255:EGF Family of Proteins; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D005576:Colforsin; D011374:Progesterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D066246:ErbB Receptors