Human chorionic gonadotropin induces c-myc mRNA expression via TSH receptor in FRTL-5 rat thyroid cells.
To elucidate the gene regulation of the thyroid-cell growth-promoting activity by human chorionic gonadotropin (hCG), we investigated the effect of hCG on c-myc proto-oncogene expression in cultured rat FRTL-5 cells by the Northern blot method. hCG induced c-myc mRNA expression, which peaked at 60-120 min. A dose-dependent increase in c-myc mRNA levels was also ascertained. In the presence of crude immunoglobulin G (IgG) from 2 patients with primary hypothyroidism who had blocking type TSH-receptor antibody, c-myc mRNA expressions induced by hCG were decreased to 82% and 62%, compared with that in the presence of normal IgG. The present results suggest that the expression of c-myc mRNA is a part of the molecular mechanism through which hCG regulates the proliferation of thyroid cells, and that hCG-induced c-myc mRNA expression is presumed to be mediated in part by TSH receptors.
Yoshimura
M
M
Second Department of Internal Medicine, Kansai Medical University, Osaka, Japan.
Nishikawa
M
M
Mori
Y
Y
Yoshikawa
N
N
Horimoto
M
M
Toyoda
N
N
Inada
M
M
D000236:Adenoma; D000818:Animals; D015152:Blotting, Northern; D002455:Cell Division / Q000187:drug effects; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects*; D016259:Genes, myc / Q000235:genetics*; D007037:Hypothyroidism / Q000276:immunology; D007074:Immunoglobulin G; D007700:Kinetics; D000090063:Proto-Oncogene Mas; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D011989:Receptors, Thyrotropin / Q000502:physiology*; D013961:Thyroid Gland / Q000166:cytology / Q000378:metabolism*; D013964:Thyroid Neoplasms; D014407:Tumor Cells, Cultured
D006063:Chorionic Gonadotropin; D007074:Immunoglobulin G; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D012333:RNA, Messenger; D011989:Receptors, Thyrotropin