Ethanol blocks the cold-induced increase in thyrotropin-releasing hormone mRNA in paraventricular nuclei but not the cold-induced increase in thyrotropin.
The effects of a single intraperitoneal injection of ethanol (3 g/kg b.wt.) on the hypothalamic-pituitary-thyroid system was explored as a possible explanation of the hypothermic effect of ethanol. Serum thyroid hormones were significantly reduced by ethanol injection, but ethanol did not affect the cold-induced increase in serum thyroid hormones or thyroid-stimulating hormone (TSH). Since cold-exposure stimulates serum levels of TSH and thyroid hormones by stimulating thyroid-releasing hormone (TRH) release from neurons of the PVN, these findings demonstrate that ethanol did not block pituitary response to TRH or thyroid response to TSH. Paradoxically, ethanol increased cellular levels of TRH mRNA in the paraventricular nucleus (PVN), and blocked the cold-induced increase in TRH mRNA, suggesting that ethanol uncouples the regulation of TRH gene expression from the regulation of TRH release specifically in neurons of the PVN. Measurements of the effects of ethanol on TRH mRNA in thalamus, and beta-actin, vasopressin, somatostatin and corticotropin-releasing hormone (CRH) mRNAs in the PVN in addition to TRH mRNA revealed very specific effects of ethanol on the TRH neuronal system.
Department of Anatomy and Neurobiology, University of Missouri School of Medicine, Columbia 65212.
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Zoeller
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Rudeen
D000818:Animals; D001483:Base Sequence; D001833:Body Temperature Regulation / Q000187:drug effects; D003080:Cold Temperature; D003346:Corticotropin-Releasing Hormone / Q000096:biosynthesis / Q000235:genetics; D003864:Depression, Chemical; D000431:Ethanol / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000378:metabolism; D007035:Hypothermia / Q000139:chemically induced / Q000503:physiopathology; D008297:Male; D008969:Molecular Sequence Data; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000096:biosynthesis / Q000235:genetics; D013961:Thyroid Gland / Q000187:drug effects / Q000378:metabolism; D013963:Thyroid Hormones / Q000097:blood; D013972:Thyrotropin / Q000096:biosynthesis* / Q000235:genetics; D013973:Thyrotropin-Releasing Hormone / Q000096:biosynthesis* / Q000235:genetics
D012333:RNA, Messenger; D013963:Thyroid Hormones; D000431:Ethanol; D013004:Somatostatin; D013973:Thyrotropin-Releasing Hormone; D013972:Thyrotropin; D003346:Corticotropin-Releasing Hormone