Potential role of G-protein-coupled receptor 30 (GPR30) in estradiol-17beta-stimulated IGF-I mRNA expression in bovine satellite cell cultures.
Androgenic and estrogenic steroids enhance muscle growth in animals and humans. Estradiol-17beta (E2) and trenbolone acetate (TBA) (a synthetic testosterone analog) increased IGF-I mRNA expression in bovine muscle satellite cell (BSC) cultures. The goal of this study was to evaluate the mechanisms responsible for this increase by evaluating the effects of ICI 182 780 (an E2 receptor antagonist), flutamide (an androgen receptor inhibitor), G1 (a GPR30 agonist), and BSA-conjugated E2 on E2 and/or TBA-stimulated IGF-I mRNA expression in BSC cultures. Flutamide completely suppressed TBA-stimulated IGF-I mRNA expression in BSC cultures. ICI 182 780 did not suppress E2-stimulated IGF-I mRNA expression and 100 nM ICI 182 780 enhanced (93%, p<0.05) IGF-I mRNA levels in BSC cultures. G1 (100 nM) stimulated IGF-I mRNA expression (100%, p<0.05) but had no effect on proliferation in BSC cultures. E2-BSA, which cannot cross the cell membrane, stimulated IGF-I mRNA expression (approximately 100%, p<0.05) in BSC but even at extremely high concentrations had no effect on proliferation. In summary, our data indicate the E2-stimulation of proliferation and E2-stimulation of IGF-I mRNA expression in BSC cultures occur via different mechanisms. Our previous results showing that ICI 182 780 inhibited BSC proliferation and results of the current study showing lack of response to E2-BSA or G1 suggest that E2-stimulated proliferation in BSC cultures is mediated through classical estrogen receptors. Stimulation by ICI 182 780, G1 and E2-BSA suggests the E2-stimulated IGF-I mRNA expression in BSC cultures is mediated through the GPR30 receptor.
Kamanga-Sollo
E
E
Animal Growth and Development Laboratory, Department of Animal Science, University of Minnesota, 348 ABLMS, Eckles Avenue, St. Paul, MN 55108, USA.
White
M E
ME
Chung
K Y
KY
Johnson
B J
BJ
Dayton
W R
WR
D000726:Androgen Antagonists / Q000494:pharmacology; D000818:Animals; D002417:Cattle / Q000502:physiology*; D049109:Cell Proliferation / Q000187:drug effects; D056746:Cyclin G; D056766:Cyclin G1; D016213:Cyclins / Q000494:pharmacology; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology*; D004965:Estrogen Antagonists / Q000494:pharmacology; D005485:Flutamide / Q000494:pharmacology; D000077267:Fulvestrant; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis* / Q000235:genetics; D008297:Male; D018482:Muscle, Skeletal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D032496:Satellite Cells, Skeletal Muscle / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D014204:Trenbolone Acetate / Q000031:analogs & derivatives / Q000494:pharmacology
D000726:Androgen Antagonists; C534702:CCNG1 protein, human; D056746:Cyclin G; D056766:Cyclin G1; D016213:Cyclins; D004965:Estrogen Antagonists; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; C043090:estradiol-bovine serum albumin; D000077267:Fulvestrant; D012710:Serum Albumin, Bovine; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D005485:Flutamide; D014204:Trenbolone Acetate