{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T18:42:19Z","timestamp":1777920139564,"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>Radioreceptor assays with (-) [125I]-iodopindolol (IPIN) were used to describe circadian variations of \u03b2-adrenoceptors in the pineal gland of male Syrian hamsters (Mesocricetus auratus). Single-point experiments (200 pM IPIN, 8\u20139 pineals pooled per time point) showed a significant circadian variation (p &lt; 0.01) with maximal values (28.9 \u00b1 1.8 fmol\/mg protein, x \u00b1 SEM, n = 7) between 07:00 and 02:30 h, and minimal values at 04:00 (7.2 \u00b1 2.9 fmol\/mg protein, n = 3), 8 h after darkness onset. Either exposure of animals to light at night or treating dark exposed hamsters with a \u03b2-adrenergic receptor blocker, propranolol, prevented the nocturnal drop in the number of \u03b2-adrenoceptors. Scatchard analysis of saturation isotherms at 02:30, 04:00 and 08:00 h (30\u2013600 pM IPIN, one saturation experiment with 25 pineals pooled per time point) confirmed the circadian variation.<\/jats:p>","DOI":"10.1159\/000125170","type":"journal-article","created":{"date-parts":[[2008,4,2]],"date-time":"2008-04-02T11:56:21Z","timestamp":1207137381000},"page":"570-573","source":"Crossref","is-referenced-by-count":14,"title":["Circadian Variation of \u03b2-Adrenoceptor Binding Sites in the Pineal Gland of the Syrian Hamster and Prevention of the Nocturnal Reduction by Light Exposure or Propranolol Treatment"],"prefix":"10.1159","author":[{"given":"Brigitte","family":"Pangerl","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Andreas","family":"Pangerl","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Russel J.","family":"Reiter","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"David J.","family":"Jones","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\/125170","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/karger.com\/article-pdf\/doi\/10.1159\/000125170","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T19:21:34Z","timestamp":1777663294000},"score":1,"resource":{"primary":{"URL":"https:\/\/karger.com\/article\/doi\/10.1159\/000125170"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2008,4,2]]},"references-count":0,"URL":"https:\/\/doi.org\/10.1159\/000125170","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]]}}}