{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T09:35:08Z","timestamp":1777887308681,"version":"3.51.4"},"reference-count":0,"publisher":"S. Karger AG","license":[{"start":{"date-parts":[[2009,4,15]],"date-time":"2009-04-15T00:00:00Z","timestamp":1239753600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/karger.com\/pages\/terms-and-conditions"},{"start":{"date-parts":[[2009,4,15]],"date-time":"2009-04-15T00:00:00Z","timestamp":1239753600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/karger.com\/pages\/terms-and-conditions"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gerontology"],"abstract":"<jats:p>Up-regulation of brain cortex \u03b2-adrenoceptors (\u03b2ARs) can be induced by very acute stimulation with a single injection of T&lt;sub&gt;4&lt;\/sub&gt; or T&lt;sub&gt;3&lt;\/sub&gt; in young Balb\/c-nu mice. We have also shown that this very rapid receptor increase can also be demonstrated in ageing animals when stimulated with T&lt;sub&gt;3&lt;\/sub&gt; but not T&lt;sub&gt;4&lt;\/sub&gt; injection. The aim of the present paper was to verify the capability of the thymus to reverse these impairments which we often observed in other experiments on old mice and young athymic nudes. The up-regulation induced by T&lt;sub&gt;4&lt;\/sub&gt; and T&lt;sub&gt;3&lt;\/sub&gt; was studied in normal and athymic nude young, normal old, and normal old and athymic nude young mice grafted with neonatal thymus 1 month earlier. In addition, since brain cortex bears both \u03b2AR subpopulations, the eventual differential behavior of \u03b2&lt;sub&gt;1&lt;\/sub&gt;AR and \u03b2&lt;sub&gt;2&lt;\/sub&gt;AR subtypes was also investigated. Animals were injected intraperitoneally with saline, or saline containing 0.5 \u03bcg T&lt;sub&gt;3&lt;\/sub&gt; or 6.4 \u03bcg T&lt;sub&gt;4&lt;\/sub&gt; per g body weight and killed 15 or 60 min after injection. Results show that thymus can recover the modifications of basal levels as well as T3-induced up-regulation of \u03b2ARs in nude and old mice. On the contrary, impaired response to T&lt;sub&gt;4&lt;\/sub&gt; stimulation is corrected in nude but not in old mice. The peripheral conversion of T&lt;sub&gt;4&lt;\/sub&gt; into T&lt;sub&gt;3&lt;\/sub&gt; can explain their differential influence since a correct conversion only occurs in presence of an efficient \u03b2-adrenergic function. Thus, a vicious circle may occur with a decreasing number of \u03b2-adrenoceptors causing in old age altered T&lt;sub&gt;4&lt;\/sub&gt; to T&lt;sub&gt;3&lt;\/sub&gt; conversion, in turn responsible for altered \u03b2-adrenergic responsiveness to T&lt;sub&gt;4&lt;\/sub&gt;.<\/jats:p>","DOI":"10.1159\/000213862","type":"journal-article","created":{"date-parts":[[2009,4,20]],"date-time":"2009-04-20T11:36:39Z","timestamp":1240227399000},"page":"268-276","source":"Crossref","is-referenced-by-count":3,"title":["Thyroid-Thymus Interaction on Beta-Adrenoceptor Regulation during Development and Ageing"],"prefix":"10.1159","author":[{"given":"Claudio","family":"Viticchi","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Andrea","family":"Basso","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Roberto","family":"Grinta","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lucio","family":"Piantanelli","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"127","published-online":{"date-parts":[[2009,4,15]]},"container-title":["Gerontology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.karger.com\/Article\/Pdf\/213862","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/karger.com\/article-pdf\/doi\/10.1159\/000213862","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T04:08:02Z","timestamp":1777608482000},"score":1,"resource":{"primary":{"URL":"https:\/\/karger.com\/article\/doi\/10.1159\/000213862"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2009,4,15]]},"references-count":0,"URL":"https:\/\/doi.org\/10.1159\/000213862","archive":["Portico"],"relation":{},"ISSN":["0304-324X","1423-0003"],"issn-type":[{"value":"0304-324X","type":"print"},{"value":"1423-0003","type":"electronic"}],"subject":[],"published":{"date-parts":[[2009,4,15]]}}}