{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T18:43:14Z","timestamp":1777920194920,"version":"3.51.4"},"reference-count":0,"publisher":"S. Karger AG","license":[{"start":{"date-parts":[[2008,4,2]],"date-time":"2008-04-02T00:00:00Z","timestamp":1207094400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/karger.com\/pages\/terms-and-conditions"},{"start":{"date-parts":[[2008,4,2]],"date-time":"2008-04-02T00:00:00Z","timestamp":1207094400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/karger.com\/pages\/terms-and-conditions"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Neuroendocrinology"],"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-\u00b5m 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 \u00b5U\/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>","DOI":"10.1159\/000125281","type":"journal-article","created":{"date-parts":[[2008,4,2]],"date-time":"2008-04-02T11:56:21Z","timestamp":1207137381000},"page":"560-563","source":"Crossref","is-referenced-by-count":16,"title":["Exogenous Triiodothyronine Lowers Thyrotropin-Releasing Hormone Concentrations in the Specific Hypothalamic Nucleus (Paraventricular) Involved in Thyrotropin Regulation and also in Posterior Nucleus"],"prefix":"10.1159","author":[{"given":"Masanobu","family":"Yamada","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Debbie","family":"Rogers","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"John F.","family":"Wilber","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"127","published-online":{"date-parts":[[2008,4,2]]},"container-title":["Neuroendocrinology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.karger.com\/Article\/Pdf\/125281","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/karger.com\/article-pdf\/doi\/10.1159\/000125281","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T19:23:19Z","timestamp":1777663399000},"score":1,"resource":{"primary":{"URL":"https:\/\/karger.com\/article\/doi\/10.1159\/000125281"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2008,4,2]]},"references-count":0,"URL":"https:\/\/doi.org\/10.1159\/000125281","archive":["Portico"],"relation":{},"ISSN":["0028-3835","1423-0194"],"issn-type":[{"value":"0028-3835","type":"print"},{"value":"1423-0194","type":"electronic"}],"subject":[],"published":{"date-parts":[[2008,4,2]]}}}