{"doi":"10.1159/000125281","title":"Exogenous Triiodothyronine Lowers Thyrotropin-Releasing Hormone Concentrations in the Specific Hypothalamic Nucleus (Paraventricular) Involved in Thyrotropin Regulation and also in Posterior Nucleus","abstract":"<jats:p>Recent evidence indicates that thyroid hormones can regulate thyrotropin secretion in vivo in part by inhibiting thyrotropin-releasing hormone (TRH) secretion itself. Therefore, to explore whether triiodothyronine (T&lt;sub&gt;3&lt;/sub&gt;) interacts with the specific hypothalamic area involved in thyrotropin (TSH) secretory regulation, the paraventricular nucleus (PVN), Palkovitz micropunches from eight nuclear regions were obtained from 1,000-µm frozen coronal brain slices for immunoassay determinations of TRH. Rats were treated either with parenteral L-T3 for 6 days to induce experimental thyrotoxicosis, or 0.15 M saline. The induction of thyrotoxicosis was confirmed by demonstrating that mean plasma TSH concentrations fell from 108 to &lt; 10 µU/ml (p &lt; 0.01). TRH concentrations in the PVN were reduced concomitantly after L-T&lt;sub&gt;3&lt;/sub&gt; from 1.9 to 1.1 ng/mg protein (p &lt; 0.05). No reductions in TRH concentrations during T&lt;sub&gt;3&lt;/sub&gt; treatment occurred in other nuclear groupings except in the posterior hypothalamic nucleus. Total TRH content in the median eminence declined also in T&lt;sub&gt;3&lt;/sub&gt;-treated animals from 1.77 to 1.29 ng, representing a 32% reduction (p &lt; 0.01). No signifcant change was seen in the median eminence content of the TRH structurally related dipeptide, cyclo(His-Pro). The data herein indicate that experimental thyrotoxicosis in the rat is associated with a selective reduction in TRH concentrations in the PVN, documenting T3 effects upon hypothalamic TRH metabolism per se.</jats:p>","journal":"Neuroendocrinology","year":2008,"id":15807,"datarank":1.039580413009036,"base_score":3.044522437723423,"endowment":3.044522437723423,"self_citation_contribution":0.4566783656585135,"citation_network_contribution":0.5829020473505225,"self_endowment_contribution":0.4566783656585135,"citer_contribution":0.5829020473505225,"corpus_percentile":null,"corpus_rank":null,"citation_count":20,"citer_count":17,"citers_with_citation_signal":17,"citers_with_endowment":17,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":119138,"name":"Debbie Rogers","orcid":null,"position":1,"is_corresponding":false},{"id":119139,"name":"John F. Wilber","orcid":null,"position":2,"is_corresponding":false},{"id":119137,"name":"Masanobu Yamada","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"base_score":3.044522437723423,"endowment":3.044522437723423,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"2514397","pmcid":null,"openalex_id":"https://openalex.org/W2021313833","authors":[],"funders":[{"funder_name":"NIDDK NIH HHS","grant_id":"DK 37378","title":null}],"total_grants":1,"fwci":0.1787,"citation_percentile":0.5797243,"influential_citations":1,"citation_trend":[{"year":2012,"count":1},{"year":2013,"count":1},{"year":2019,"count":1},{"year":2021,"count":1}],"oa_status":"closed","license":"https://karger.com/pages/terms-and-conditions","oa_locations":[{"url":"https://www.karger.com/Article/Pdf/125281","host_type":"publisher"},{"url":"https://karger.com/article-pdf/doi/10.1159/000125281","host_type":"publisher"},{"url":"https://doi.org/10.1159/000125281","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/2514397","host_type":"repository"}],"fields_of_study":["Thyroid Disorders and Treatments","Growth Hormone and Insulin-like Growth Factors","Neuroscience of respiration and sleep","Biology","Medicine","Animals","Male","Median Eminence","Paraventricular Hypothalamic Nucleus","Rats","Rats, Inbred Strains","Thyrotropin","Thyrotropin-Releasing Hormone","Triiodothyronine"],"mesh_terms":["Animals","Male","Median Eminence","Paraventricular Hypothalamic Nucleus","Rats, Inbred Strains","Thyrotropin","Thyrotropin-Releasing Hormone","Triiodothyronine","Rats"],"keywords":["Median eminence","Internal medicine","Endocrinology","Thyrotropin-releasing hormone","Triiodothyronine","Hypothalamus","Hormone","Chemistry","Nucleus","Biology","Medicine"],"sdg_mappings":[{"sdg_number":0,"sdg_label":"Good health and well-being"}],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-06-01T19:04:24.651684Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}