Identification of Tissue Distribution and Regulation of Bovine Stearoyl-Coa Desaturase by Hormones and Nutrients

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dc.contributor.authorCampbell, Davina Elaineen
dc.contributor.committeechairCorl, Benjamin A.en
dc.contributor.committeememberHerbein, Joseph H. Jr.en
dc.contributor.committeememberPearson, Ronald E.en
dc.contributor.committeememberAkers, Robert Michaelen
dc.contributor.departmentDairy Scienceen
dc.date.accessioned2014-03-14T20:41:19Zen
dc.date.adate2007-08-24en
dc.date.available2014-03-14T20:41:19Zen
dc.date.issued2007-06-28en
dc.date.rdate2012-06-08en
dc.date.sdate2007-07-11en
dc.description.abstractStudies were conducted to investigate the tissue distribution of stearoyl-CoA desaturase-1 (SCD) and the regulation of SCD1 protein expression by dietary fat, insulin, polyunsaturated fatty acids (PUFA), and linoleic acid (cis-9, cis-12 18:2). The first study examined tissue distribution of SCD1 protein in Holstein calves (n=6/diet) fed one of four milk replacer diets for a nine wk period after which they were sacrificed. Milk replacer diets varied in fat content and were formulated and administered as follows: 0.4 kg/d 20% protein, 20% fat (20:20; CON), 0.97 kg/d (28:20; HPLF), 0.97 kg/d (28:28; HPHF), or 1.46 kg/d (28:28; HPHF+). Samples of subcutaneous adipose tissue (AT), perirenal AT, omental AT, duodenum, proximal jejunum, distal jejunum, ileum, and liver were collected from calves fed the HPHF+ diet to determine SCD1 tissue distribution. Tissue homogenates were prepared and used for Western blotting. Additionally, dietary effects were analyzed on tissues expressing SCD1 protein for all 24 calves. The second study investigated the regulation of SCD1 protein expression by insulin, fatty acids increasing in degree of unsaturation, and increasing concentrations of linoleic (18:2) acid. Subcutaneous AT was collected from Smith Valley Meats in Rich Creek, VA and used to prepare explants cultured in treatment media for 24 h. Treatments consisted of insulin at 0, 7, 14, and 21 nM; stearic (18:0), oleic (18:1), linoleic (18:2), and linolenic (18:3) acids at 100 μM; and linoleic (18:2) acid at concentrations of 0, 25, 50, 75, and 100 μM. Tissue explant homogenates were used for Western blotting to detect SCD1. In the first study, we found that SCD1 protein was detectable in subcutaneous AT, perirenal AT, and omental AT; however, it was not detectable in liver or small intestine samples. Also, the HPHF+ diet increased SCD1 protein expression in subcutaneous AT and perireanl AT. In the second study, SCD1 protein expression increased linearly with insulin concentration. There was no fatty acid treatment effect, but there was a negative linear effect with increase in degree of unsaturation. Finally, there was no effect on SCD1 protein expression with linoleic acid increasing in concentration. In conclusion, results indicate that SCD1 protein expression was detected in bovine AT depots, regulated by dietary fat, insulin, and by PUFA .en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-07112007-175956en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-07112007-175956/en
dc.identifier.urihttp://hdl.handle.net/10919/33967en
dc.publisherVirginia Techen
dc.relation.haspartDavinaECampbellThesis.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectcalvesen
dc.subjectfaten
dc.subjectexplantsen
dc.subjectpolyunsaturated fatty acidsen
dc.subjectregulationen
dc.subjectstearoyl-CoA desaturaseen
dc.subjecttissue distributionen
dc.titleIdentification of Tissue Distribution and Regulation of Bovine Stearoyl-Coa Desaturase by Hormones and Nutrientsen
dc.typeThesisen
thesis.degree.disciplineDairy Scienceen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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