{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,30]],"date-time":"2025-10-30T06:52:53Z","timestamp":1761807173888},"reference-count":27,"publisher":"Cambridge University Press (CUP)","issue":"1","license":[{"start":{"date-parts":[[2007,3,9]],"date-time":"2007-03-09T00:00:00Z","timestamp":1173398400000},"content-version":"unspecified","delay-in-days":9017,"URL":"https:\/\/www.cambridge.org\/core\/terms"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Br J Nutr"],"published-print":{"date-parts":[[1982,7]]},"abstract":"<jats:p>1. Five monotocous and twoditocous Scottish Blackface ewes with indwelling catheters in an umbilical artery and vein of one foetus only and in both maternal jugular veins were used.<\/jats:p><jats:p>2. Experiments were conducted over a period of 2 d when [<jats:sup>I4<\/jats:sup>C]urea was infused intravenously over 9 h into either the mother or foetus, separate days being used for each infusion. Two series of experiments were completed, one in well-nourished and the other in undernourished sheep at 125\u2013141) and 138\u2013143 d of gestation respectively.<\/jats:p><jats:p>3. Plasma urea specific radioactivities of the mother and infused foetus at plateau were used to determine the urea flux-rates within and between mother and foetus. The mean rate of foetal urea production (<jats:italic>F<\/jats:italic><jats:sub>fo<\/jats:sub>) was 1.45 and 1.63 mg\/min per kg foetus in well-nourished and undernourished ewes respectively. The corresponding rates of maternal urea production (<jats:italic>F<\/jats:italic><jats:sub>mo<\/jats:sub>) were 0.49 and 0.37 mg\/min per kg live weight respectively and there was a close correlation between the rate of maternal urea disposal (<jats:italic>F<\/jats:italic><jats:sub>om<\/jats:sub>) and the dietary nitrogen intake.<\/jats:p><jats:p>4. The values of<jats:italic>F<\/jats:italic><jats:sub>fo<\/jats:sub>were used to calculate the maximum potential for foetal gluconeogenesis from deaminated amino acids. These calculations were compared with published information on the over-all rates of foetal gluconeo genesis in well-nourished ewes.<\/jats:p><jats:p>5. The foetal entry rate of urea expressed on a body-weight basis was high, approximately 8.5 times that of the mother, but it was a threefold overestimate of<jats:italic>F<\/jats:italic><jats:sub>fo<\/jats:sub>. The maternal entry rate was 1.3 times<jats:italic>F<\/jats:italic><jats:sub>mo<\/jats:sub>and the significance of this in relation to assessing differences in urea entry rates in pregnant and non-pregnant sheep is discussed.<\/jats:p>","DOI":"10.1079\/bjn19820086","type":"journal-article","created":{"date-parts":[[2005,5,24]],"date-time":"2005-05-24T23:20:35Z","timestamp":1116976835000},"page":"49-58","source":"Crossref","is-referenced-by-count":5,"title":["Foetal and maternal rates of urea production and disposal in well-nourished and undernourished sheep"],"prefix":"10.1017","volume":"48","author":[{"given":"J. C.","family":"Hodgson","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"D. J.","family":"Mellor","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"A. C.","family":"Field","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"56","published-online":{"date-parts":[[2007,3,9]]},"reference":[{"key":"S0007114582000099_ref010","first-page":"137","volume":"1","author":"Holzman","year":"1979","journal-title":"J. devel. Physiol."},{"key":"S0007114582000099_ref026","doi-asserted-by":"publisher","DOI":"10.1177\/000456326900600108"},{"key":"S0007114582000099_ref003","first-page":"211","volume":"5","author":"Faichney","year":"1980","journal-title":"Proc. Nutr. Soc. Aust."},{"key":"S0007114582000099_ref021","doi-asserted-by":"publisher","DOI":"10.1016\/0304-4165(80)90423-7"},{"key":"S0007114582000099_ref022","first-page":"197","volume-title":"Fetal and Newborn Cardiovascular Physiology","volume":"2","author":"Schreiner","year":"1978"},{"key":"S0007114582000099_ref014","doi-asserted-by":"publisher","DOI":"10.1113\/expphysiol.1979.sp002462"},{"key":"S0007114582000099_ref013","doi-asserted-by":"publisher","DOI":"10.1042\/bst0061152"},{"key":"S0007114582000099_ref008","doi-asserted-by":"publisher","DOI":"10.1042\/bj1960179"},{"key":"S0007114582000099_ref002","doi-asserted-by":"publisher","DOI":"10.1079\/BJN19800007"},{"key":"S0007114582000099_ref020","first-page":"E462","volume":"233","author":"Prior","year":"1977","journal-title":"Am. J. Physiol."},{"key":"S0007114582000099_ref024","doi-asserted-by":"publisher","DOI":"10.1203\/00006450-197410000-00003"},{"key":"S0007114582000099_ref001","first-page":"382","volume-title":"Barcroft's Centenary Symposium on Foetal and Neonatal Physiology","author":"Battaglia","year":"1973"},{"key":"S0007114582000099_ref016","author":"Mellor","year":"1982","journal-title":"Res. vet. Sci."},{"key":"S0007114582000099_ref011","doi-asserted-by":"crossref","first-page":"361","DOI":"10.1542\/peds.50.3.361","volume":"50","author":"James","year":"1972","journal-title":"Pediatrics, Springfield"},{"key":"S0007114582000099_ref017","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1967.22.6.1171"},{"key":"S0007114582000099_ref025","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1016\/S0021-9258(18)43098-0","volume":"160","author":"Somogyi","year":"1945","journal-title":"J. biol. Chem."},{"key":"S0007114582000099_ref009","doi-asserted-by":"publisher","DOI":"10.3181\/00379727-156-39868"},{"key":"S0007114582000099_ref018","doi-asserted-by":"publisher","DOI":"10.1079\/BJN19700095"},{"key":"S0007114582000099_ref027","doi-asserted-by":"publisher","DOI":"10.1017\/S0021859600022929"},{"key":"S0007114582000099_ref015","doi-asserted-by":"crossref","first-page":"198","DOI":"10.1016\/S0034-5288(18)32581-5","volume":"30","author":"Mellor","year":"1981","journal-title":"Res. vet. Sci."},{"key":"S0007114582000099_ref007","doi-asserted-by":"publisher","DOI":"10.1042\/bj1860739"},{"key":"S0007114582000099_ref023","volume-title":"Tracer Methods for In Vivo Kinetics: Theory and Applications","author":"Shipley","year":"1972"},{"key":"S0007114582000099_ref012","doi-asserted-by":"publisher","DOI":"10.1172\/JCI108598"},{"key":"S0007114582000099_ref004","doi-asserted-by":"publisher","DOI":"10.1136\/jcp.13.2.156"},{"key":"S0007114582000099_ref019","doi-asserted-by":"crossref","first-page":"E208","DOI":"10.1152\/ajpcell.1980.239.5.C208","volume":"239","author":"Prior","year":"1980","journal-title":"Am. J. Physiol."},{"key":"S0007114582000099_ref005","doi-asserted-by":"crossref","first-page":"372","DOI":"10.1542\/peds.50.3.372","volume":"50","author":"Gresham","year":"1972","journal-title":"Pediatrics, Springfield"},{"key":"S0007114582000099_ref006","doi-asserted-by":"publisher","DOI":"10.1079\/PNS19770006"}],"container-title":["British Journal of Nutrition"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.cambridge.org\/core\/services\/aop-cambridge-core\/content\/view\/S0007114582000099","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,1,26]],"date-time":"2024-01-26T02:52:23Z","timestamp":1706237543000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.cambridge.org\/core\/product\/identifier\/S0007114582000099\/type\/journal_article"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1982,7]]},"references-count":27,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1982,7]]}},"alternative-id":["S0007114582000099"],"URL":"https:\/\/doi.org\/10.1079\/bjn19820086","relation":{},"ISSN":["0007-1145","1475-2662"],"issn-type":[{"value":"0007-1145","type":"print"},{"value":"1475-2662","type":"electronic"}],"subject":[],"published":{"date-parts":[[1982,7]]}}}