title: TRH and TRH-like peptide expression in rat following episodic or continuous corticosterone.
abstract: Sustained abnormalities of glucocorticoid levels have been associated with neuropsychiatric illnesses such as major depression, posttraumatic stress disorder (PTSD), panic disorder, and obsessive compulsive disorder. The pathophysiological effects of glucocorticoids may depend not only on the amount of glucocorticoid exposure but also on its temporal pattern, since it is well established that hormone receptors are down-regulated by continuously elevated cognate hormones. We have previously reported that TRH (pGlu-His-Pro-NH2) and TRH-like peptides (pGlu-X-Pro-NH2) have endogenous antidepressant-like properties and mediate or modulate the acute effects of a single i.p. injection of high dose corticosterone (CORT) in rats. For these reasons, two accepted methods for inducing chronic hyperglucocorticoidemia have been compared for their effects on brain and peripheral tissue levels of TRH and TRH-like peptides in male, 250 g, Sprague-Dawley rats: (1) the dosing effect of CORT hemisuccinate in drinking water, and (2) s.c. slow-release pellets. Overall, there were 93% more significant changes in TRH and TRH-like peptide levels in brain and 111% more in peripheral tissues of those rats ingesting various doses of CORT in drinking water compared to those with 1-3 s.c. pellets. We conclude that providing rats with CORT in drinking water is a convenient model for the pathophysiological effects of hyperglucocorticoidemia in rodents.
authors.affiliation: Research Services, VA Greater Los Angeles Healthcare System, USA. Eugene.Pekary@va.gov
authors.forename: Albert Eugene
authors.initials: AE
authors.lastname: Pekary
authors.forename: Albert
authors.initials: A
authors.lastname: Sattin
authors.forename: James
authors.initials: J
authors.lastname: Blood
authors.forename: Stephanie
authors.initials: S
authors.lastname: Furst
mesh_terms: D000284:Administration, Oral; D000704:Analysis of Variance; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D003345:Corticosterone / Q000008:administration & dosage* / Q000097:blood; D004305:Dose-Response Relationship, Drug; D004326:Drinking; D004334:Drug Administration Schedule; D016503:Drug Delivery Systems; D004343:Drug Implants; D004822:Epididymis / Q000033:anatomy & histology; D008297:Male; D009929:Organ Size; D010179:Pancreas / Q000033:anatomy & histology; D011467:Prostate / Q000033:anatomy & histology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013737:Testis / Q000033:anatomy & histology; D013973:Thyrotropin-Releasing Hormone / Q000031:analogs & derivatives / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
chemical_list: D004343:Drug Implants; D014284:Triiodothyronine; D013973:Thyrotropin-Releasing Hormone; D013974:Thyroxine; D003345:Corticosterone