title: Effects of thyrotropin-releasing hormone on prolactin, growth hormone and corticosterone secretions in adult male rats treated with pentobarbital or morphine.
abstract: Thyrotropin-releasing hormone (TRH) injected either IP (10 mg/kg) or intraventricularly (10 mug/rat) antagonized the pentobarbital-induced secretion of prolactin (PRL). This effect was not blocked by propranolol. In thyroidectomized animals the effect was not apparent; tri-iodothyronine (T3) injection was however ineffective. The injections of luteinizing hormone-releasing hormone (LH-RH) and of melanocyte stimulating hormone release-inhibiting factor (MIF) were also ineffective. Of six TRH analogues, only those containing histidine antagonized pentobarbital-induced PRL release, but none modified plasma levels of growth hormone (GH) or corticosterone (B). Brain levels of serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were not modified by TRH. Morphine-induced secretion of PRL and GH was also significantly antagonized by TRH. Since pentobarbital and morphine-induced hormonal changes are probably exerted through a central nervous system depressant action, these data indicate that TRH can influence brain activity through an extrapituitary mechanism.
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D003345:Corticosterone / Q000378:metabolism*; D013006:Growth Hormone / Q000378:metabolism*; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D007276:Injections, Intraventricular; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D010424:Pentobarbital / Q000494:pharmacology*; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D012701:Serotonin / Q000378:metabolism; D013973:Thyrotropin-Releasing Hormone / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D013973:Thyrotropin-Releasing Hormone; D009020:Morphine; D011388:Prolactin; D013006:Growth Hormone; D010424:Pentobarbital; D003345:Corticosterone