{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T14:16:54Z","timestamp":1782483414438,"version":"3.54.5"},"reference-count":0,"publisher":"Portland Press Ltd.","issue":"1","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1998,5,15]]},"abstract":"<jats:p>\u03b1-Tocopherol (\u03b1TocH) is transported in association with lipoproteins in the aqueous milieu of the plasma. Although up to 50% of circulating \u03b1TocH is transported by high-density lipoproteins (HDLs), little is known about the mechanisms of uptake of HDL-associated \u03b1TocH. During the current study, human apolipoprotein (apo)E-free HDL subclass 3 (HDL3) labelled with [14C]\u03b1TocH was used to investigate uptake mechanisms of HDL3-associated \u03b1TocH by a permanent hepatoblastoma cell line (HepG2). HDL3-associated \u03b1TocH was taken up independently of HDL3 holoparticles in excess of apoA-I comparable with the non-endocytotic delivery of cholesteryl esters to cells termed the \u2018selective \u2019 cholesteryl ester uptake pathway. Experiments with unlabelled HDL3 demonstrated net mass transfer of \u03b1TocH to HepG2 cells. Time-dependent studies with [14C]\u03b1TocH-labelled HDL3 revealed tracer uptake in 80-fold excess of apoA-I and in 4-fold excess of cholesteryl linoleate. In addition to HLDs, low-density lipoprotein (LDL)-associated \u03b1TocH was also taken up in excess of holoparticles, although to a lesser extent. These findings were confirmed with unlabelled lipoprotein preparations, in which HDL3 displayed a 2- to 3-fold higher \u03b1TocH donor efficiency than LDLs (lipoproteins adjusted for equal amounts of \u03b1TocH). An important factor affecting particle-independent uptake of \u03b1TocH was the cellular cholesterol content (a 2-fold increase in cellular cholesterol levels resulted in a 2.3-fold decrease in uptake). Pulse\u2013chase studies demonstrated that some of the HDL3-associated \u03b1TocH taken up independently of holoparticle uptake was resecreted along with a newly synthesized apoB-containing lipoprotein fraction.<\/jats:p>","DOI":"10.1042\/bj3320057","type":"journal-article","created":{"date-parts":[[2015,8,10]],"date-time":"2015-08-10T22:02:02Z","timestamp":1439244122000},"page":"57-65","update-policy":"https:\/\/doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":42,"title":["High-density lipoprotein (HDL3)-associated \u03b1-tocopherol is taken up by HepG2 cells via the selective uptake pathway and resecreted with endogenously synthesized apo-lipoprotein B-rich lipoprotein particles"],"prefix":"10.1042","volume":"332","author":[{"given":"Daniel","family":"GOTI","sequence":"first","affiliation":[{"name":"Department of Medical Biochemistry, University of Graz, Harrachgasse 21, 8010 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Helga","family":"REICHER","sequence":"additional","affiliation":[{"name":"Department of Medical Biochemistry, University of Graz, Harrachgasse 21, 8010 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ernst","family":"MALLE","sequence":"additional","affiliation":[{"name":"Department of Medical Biochemistry, University of Graz, Harrachgasse 21, 8010 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gerhard M.","family":"KOSTNER","sequence":"additional","affiliation":[{"name":"Department of Medical Biochemistry, University of Graz, Harrachgasse 21, 8010 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ute","family":"PANZENBOECK","sequence":"additional","affiliation":[{"name":"Department of Medical Biochemistry, University of Graz, Harrachgasse 21, 8010 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wolfgang","family":"SATTLER","sequence":"additional","affiliation":[{"name":"Department of Medical Biochemistry, University of Graz, Harrachgasse 21, 8010 Graz, Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"288","container-title":["Biochemical Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/332\/1\/57\/631084\/bj3320057.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/332\/1\/57\/631084\/bj3320057.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,11,24]],"date-time":"2021-11-24T01:03:49Z","timestamp":1637715829000},"score":1,"resource":{"primary":{"URL":"https:\/\/portlandpress.com\/biochemj\/article\/332\/1\/57\/37554\/High-density-lipoprotein-HDL3-associated"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1998,5,15]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1998,5,15]]}},"URL":"https:\/\/doi.org\/10.1042\/bj3320057","relation":{},"ISSN":["0264-6021","1470-8728"],"issn-type":[{"value":"0264-6021","type":"print"},{"value":"1470-8728","type":"electronic"}],"subject":[],"published":{"date-parts":[[1998,5,15]]}}}