{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T18:57:40Z","timestamp":1777921060468,"version":"3.51.4"},"reference-count":0,"publisher":"S. Karger AG","license":[{"start":{"date-parts":[[2008,4,9]],"date-time":"2008-04-09T00:00:00Z","timestamp":1207699200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/karger.com\/pages\/terms-and-conditions"},{"start":{"date-parts":[[2008,4,9]],"date-time":"2008-04-09T00:00:00Z","timestamp":1207699200000},"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>Lewis (LEW\/N) and Fischer (F344\/N) rats are histocompatible inbred strains characterized, respectively, by susceptibility and resistance to inflammatory disease. The susceptibility of LEW\/N rats to inflammation has been associated with deficient corticotropin-releasing hormone (CRH), ACTH, and corticosterone responses to inflammatory stimuli, specifically attributed to a global impairment in hypothalamic CRH neuron function. In contrast to the LEW\/N rats, F344\/N rats demonstrate an intact hypothalamic-pituitary-adrenal (HPA) axis. Melatonin, a neurohormone initially isolated in the pineal gland, has been implicated with inhibition of the HPA axis. To investigate melatonin synthesis and secretion in LEW\/N and F344\/N rats, we examined the diurnal activity of pineal arylalkylamine N-acetyltransferase (NATl), the rate-limiting enzyme in melatonin biosynthesis, which demonstrates circadian rhythmicity, as well as the diurnal levels of serum melatonin, in both strains. Arylamine N-acetyltransferase (NAT2), a related enzyme activity, thought not to be regulated in a circadian manner, was examined as a control of NATl activity. Pineal NATl activity peak was observed later and reached significantly higher levels in LEW\/N than in F344\/N rats. Serum melatonin levels reflected the circadian pattern of the NATl activity, without, however, showing any quantitative differences between the two strains. Time-course of pineal NATl activity response to \u03b2-adrenergic stimulation was parallel in the two rat strains, whereas the magnitude of the response was greater in LEW\/N than in F344\/N rats. No circadian or major quantitative differences in NAT2 activity were found between the two strains. Size-exclusion HPLC chromatograms of NATl activity revealed similar patterns in both rat strains. These findings demonstrate a difference in the circadian and \u03b2-adrenergic-stimulated regulation of melatonin synthesis in the two rat strains.<\/jats:p>","DOI":"10.1159\/000126990","type":"journal-article","created":{"date-parts":[[2008,4,10]],"date-time":"2008-04-10T04:37:20Z","timestamp":1207802240000},"page":"71-78","source":"Crossref","is-referenced-by-count":0,"title":["Differences in Arylalkylamine N-Acetyltransferase Activity between Inflammatory Disease-Susceptible Lewis and -Resistant Fischer Rats"],"prefix":"10.1159","author":[{"given":"George","family":"Mastorakos","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Vladimir K.","family":"Patchev","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gerald J.","family":"Chader","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"George P.","family":"Chrousos","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Stephen J.","family":"Gaudet","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"127","published-online":{"date-parts":[[2008,4,9]]},"container-title":["Neuroendocrinology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.karger.com\/Article\/Pdf\/126990","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/karger.com\/article-pdf\/doi\/10.1159\/000126990","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T19:44:05Z","timestamp":1777664645000},"score":1,"resource":{"primary":{"URL":"https:\/\/karger.com\/article\/doi\/10.1159\/000126990"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2008,4,9]]},"references-count":0,"URL":"https:\/\/doi.org\/10.1159\/000126990","archive":["Portico"],"relation":{},"ISSN":["0028-3835","1423-0194"],"issn-type":[{"value":"0028-3835","type":"print"},{"value":"1423-0194","type":"electronic"}],"subject":[],"published":{"date-parts":[[2008,4,9]]}}}