Novel expression of human chorionic gonadotropin/luteinizing hormone receptor gene in brain.
LH from anterior pituitary and hCG from placenta bind to a common receptor in gonadal and nongonadal reproductive tissues. There have been numerous examples suggesting that the brain may also contain hCG/LH receptors, yet there has been no evidence for their existence so far. We now demonstrate by reverse transcription-nested polymerase chain reaction and northern blotting that the rat brain contains hCG/LH receptor mRNA. A major receptor transcript of 2.6 kilobases and minor transcripts of 1.8 and 4.4 kilobases were found. Western immunoblotting, ligand blotting, and covalent receptor cross-linking studies have shown that rat brain also contains an 80-kilodalton receptor protein that can bind hCG and hLH, but not hFSH. Rat testis used as a positive control showed a higher abundance of multiple transcripts and an 80-kilodalton receptor protein that can bind [125I]hCG. Rat liver used as a negative control did not contain any receptor transcripts or protein. In situ hybridization, dot blotting, immunocytochemistry, and topical autoradiography have revealed that hCG/LH receptors are present in rat hippocampus; dentate gyrus; hypothalamus; cerebellum; choroid plexus; ependymal cells of third, fourth, and lateral ventricles; cortex; brainstem; bovine hypothalamus; and human area postrema. These novel findings could potentially explain numerous previous observations and suggest new possibilities concerning the regulation of brain functions by hCG and LH.
Lei
Z M
ZM
Department of Obstetrics/Gynecology, University of Louisville School of Medicine, Kentucky 40292.
Rao
C V
CV
Kornyei
J L
JL
Licht
P
P
Hiatt
E S
ES
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism*; D006063:Chorionic Gonadotropin / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007986:Luteinizing Hormone / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011974:Receptors, LH / Q000235:genetics* / Q000378:metabolism; D014018:Tissue Distribution
D006063:Chorionic Gonadotropin; D012333:RNA, Messenger; D011974:Receptors, LH; D007986:Luteinizing Hormone