{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,21]],"date-time":"2026-02-21T03:21:23Z","timestamp":1771644083670,"version":"3.50.1"},"reference-count":0,"publisher":"Portland Press Ltd.","issue":"1","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1971,8,1]]},"abstract":"<jats:p>1. The activity of rat liver microsomal drug-metabolizing enzymes was determined at various ages between 6 and 100 days post natum. The enzymes studied were: aromatic hydroxylases by using as substrate biphenyl, which is metabolized by oxidation to 2- and 4-hydroxybiphenyl; nitroreductase by using p-nitrobenzoate as substrate, which is metabolized by reduction to p-aminobenzoate; glucuronyl synthetase by using 4-methylumbelliferone as the substrate, which is conjugated to give 4-methylumbelliferone glucuronide, and cytochrome P-450, which is regarded as the major terminal mixed-function oxidase in hepatic microsomal hydroxylations. 2. The activity of biphenyl 2-hydroxylase reached a peak at 21 days, biphenyl 4-hydroxylase and 4-methyl glucuronyl transferase at 24 days, cytochrome P-450 at 31 days, and p-nitrobenzoate reductase at 38 days of age. After the peak activity had been reached, the activity of each enzyme decreased with age, and in the case of biphenyl 2-hydroxylase the activity fell to a negligible value at 52 days of age. 3. Neither the addition of Triton X-100 to the incubation medium nor the treatment of the animals with phenobarbital resulted in any increase in the activity of biphenyl 2-hydroxylase at 52 days of age. 4. The activity of biphenyl 2-hydroxylase was threefold higher in rats fed on a synthetic diet than in rats fed on a commercial stock diet. 5. These findings are discussed.<\/jats:p>","DOI":"10.1042\/bj1240019","type":"journal-article","created":{"date-parts":[[2015,8,13]],"date-time":"2015-08-13T21:37:43Z","timestamp":1439501863000},"page":"19-24","update-policy":"https:\/\/doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":68,"title":["Effect of development on the activity of microsomal drug-metabolizing enzymes in rat liver"],"prefix":"10.1042","volume":"124","author":[{"given":"T. K.","family":"Basu","sequence":"first","affiliation":[{"name":"Department of Biochemistry, University of Surrey, Guildford, Surrey, U.K."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"J. W. T.","family":"Dickerson","sequence":"additional","affiliation":[{"name":"Department of Biochemistry, University of Surrey, Guildford, Surrey, U.K."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"D. V. W.","family":"Parke","sequence":"additional","affiliation":[{"name":"Department of Biochemistry, University of Surrey, Guildford, Surrey, U.K."}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"288","container-title":["Biochemical Journal"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/124\/1\/19\/771482\/bj1240019.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/portlandpress.com\/biochemj\/article-pdf\/124\/1\/19\/771482\/bj1240019.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,11,26]],"date-time":"2021-11-26T19:13:15Z","timestamp":1637953995000},"score":1,"resource":{"primary":{"URL":"https:\/\/portlandpress.com\/biochemj\/article\/124\/1\/19\/17290\/Effect-of-development-on-the-activity-of"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1971,8,1]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1971,8,1]]}},"URL":"https:\/\/doi.org\/10.1042\/bj1240019","relation":{},"ISSN":["0306-3283"],"issn-type":[{"value":"0306-3283","type":"print"}],"subject":[],"published":{"date-parts":[[1971,8,1]]}}}