{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,28]],"date-time":"2025-10-28T18:24:05Z","timestamp":1761675845550},"reference-count":0,"publisher":"Canadian Science Publishing","issue":"4","license":[{"start":{"date-parts":[[1985,4,1]],"date-time":"1985-04-01T00:00:00Z","timestamp":481161600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/www.nrcresearchpress.com\/page\/about\/CorporateTextAndDataMining"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Can. J. Physiol. Pharmacol."],"published-print":{"date-parts":[[1985,4,1]]},"abstract":"<jats:p> Perinatal thyroid dysfunction in the rat leads to permanent alterations in pituitary TSH secretion in the adult animal. Thus, neonatal hyperthyroidism (NH) and perinatal hypothyroidism (PH) both result in apparent increased pituitary sensitivity to the feedback effects of thyroid hormones in the adult rat. To determine if increased intrapituitary generation of triiodothyronine (T<jats:sub>3<\/jats:sub>) might account for these observations, we measured thyroxine (T<jats:sub>4<\/jats:sub>) 5\u2032-deiodinase activity in pituitary homogenates of adult NH and PH rats. NH was induced by injecting neonatal rats with 12 daily sc injections of T<jats:sub>4<\/jats:sub> (0.4\u2002\u03bcg\/g body weight (BW)). Control rats received vehicle alone. PH was induced by administering 0.05% 6-n-propylthiouracil in the drinking water to pregnant dams from the 16th day of gestation through the 12th day postpartum. Thereafter, a normal water supply was substituted. NH and PH rats were allowed to mature and were sacrificed at 105 days of age. Serum T<jats:sub>4<\/jats:sub>, T<jats:sub>3<\/jats:sub>, and TSH concentrations were measured by radioimmunoassay. Pituitary T<jats:sub>4<\/jats:sub> 5\u2032-deiodinase activity was assessed by the measurement of T<jats:sub>3<\/jats:sub> formation by pituitary homogenates incubated in the presence of 0.65\u2002\u03bcM T<jats:sub>4<\/jats:sub> and 100\u2002mM dithiothreitol at 37 \u00b0C for 90\u2002min. Body weights of adult NH and PH rats were slightly but not significantly decreased compared with control rats. Relative pituitary gland weight (milligrams per 100\u2002g BW) was significantly decreased in adult PH rats (P\u2002&lt; 0.005) but not in adult NH rats. In adult NH rats, serum T<jats:sub>4<\/jats:sub> and T<jats:sub>3<\/jats:sub> concentrations were significantly decreased (P\u2002&lt; 0.01) compared with control rats. Serum TSH concentrations were similar. No significant differences in serum T<jats:sub>4<\/jats:sub>, T<jats:sub>3<\/jats:sub>, and TSH concentrations were noted between adult PH and control rats. Pituitary T<jats:sub>4<\/jats:sub> 5\u2032-deiodinase activity was significantly increased in both adult NH and PH rats compared with controls (NH &gt; PH &gt; control; P\u2002&lt; 0.005, and P\u2002&lt; 0.05, respectively). These data indicate that pituitary T<jats:sub>4<\/jats:sub> 5\u2032-deiodinase activity is significantly increased in adult NH and PH rats. Increased pituitary T<jats:sub>4<\/jats:sub> 5\u2032-monodeiodination may explain, in part, the apparent increased thyrotroph sensitivity to feedback effects of thyroid hormone in these animals. <\/jats:p>","DOI":"10.1139\/y85-050","type":"journal-article","created":{"date-parts":[[2011,4,24]],"date-time":"2011-04-24T08:53:21Z","timestamp":1303635201000},"page":"279-282","source":"Crossref","is-referenced-by-count":4,"title":["Increased pituitary thyroxine 5\u2032-deiodinase activity in adult rats rendered hyper- or hypo-thyroid during perinatal life"],"prefix":"10.1139","volume":"63","author":[{"given":"Peter","family":"Walker","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"155","container-title":["Canadian Journal of Physiology and Pharmacology"],"original-title":[],"language":"en","link":[{"URL":"http:\/\/www.nrcresearchpress.com\/doi\/pdf\/10.1139\/y85-050","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2020,1,5]],"date-time":"2020-01-05T16:21:51Z","timestamp":1578241311000},"score":1,"resource":{"primary":{"URL":"http:\/\/www.nrcresearchpress.com\/doi\/10.1139\/y85-050"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1985,4,1]]},"references-count":0,"journal-issue":{"issue":"4","published-print":{"date-parts":[[1985,4,1]]}},"alternative-id":["10.1139\/y85-050"],"URL":"https:\/\/doi.org\/10.1139\/y85-050","relation":{},"ISSN":["0008-4212","1205-7541"],"issn-type":[{"value":"0008-4212","type":"print"},{"value":"1205-7541","type":"electronic"}],"subject":[],"published":{"date-parts":[[1985,4,1]]}}}