Uridinediphosphate-glucuronosyltransferase (UDP-GT) Ontogeny and PCB Effects in Galliform Birds

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dc.contributor.authorMcCleary, Ryan J. R.en
dc.contributor.committeechairMcNabb, F. M. Anneen
dc.contributor.committeememberBevan, David R.en
dc.contributor.committeememberHeath, Alan G.en
dc.contributor.departmentBiologyen
dc.date.accessioned2014-03-14T20:48:57Zen
dc.date.adate2001-12-06en
dc.date.available2014-03-14T20:48:57Zen
dc.date.issued2001-06-26en
dc.date.rdate2002-12-06en
dc.date.sdate2001-12-05en
dc.description.abstractHepatic UDP-GTs are partly responsible for metabolism of the thyroid hormone, thyroxine (T4), in mammals, but little is known of UDP-GT activity in birds. To determine the ontogenic pattern of UDP-GT activity in precocial birds, we measured activity in Japanese quail (Coturnix japonica) liver at days 12 and 14 of the 16.5-day incubation, 3 perihatch stages and <1, 1, 4, 6, 7, 20 and 42 days posthatch. We used an enzymatic reaction with para-nitrophenol (pNP) as substrate that was validated for quail tissue. The pattern of UDP-GT development included low embryonic activity, increased activity beginning in the perihatch period, a peak in activity at day 4 posthatch and a return to lower activity levels from day 6 to adults. The profile of UDP-GT activity, in relation to the ontogeny of circulating T4 and triiodothyronine (T3) in quail, is consistent with UDP-GT playing a role in regulating circulating T4 and with the perihatch peak in T3 stimulating the posthatch peak in UDP-GT activity. To examine the effects of polychlorinated biphenyls (PCBs) on UDP-GT in developing precocial birds, we dosed chicken (Gallus domesticus) eggs with concentrations of PCB 126 from 0 to 0.80 ng/g egg (in sunflower oil) prior to incubation. Tissues were sampled at day 20 of the 21-day incubation and assayed for plasma hormones and UDP-GT activity. Eggs also were dosed with 0 or 0.25 ng PCB 126/g egg or with 0 or 0.64 ng/g egg of the coplanar PCB 77, allowed to hatch, and sampled at 42 days posthatch. There was no consistent pattern of altered thyroid hormones or UDP-GT activity in developing chickens exposed to either of these coplanar PCBs although previous studies indicated developmental alterations from exposure to the higher doses.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-12052001-165142en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-12052001-165142/en
dc.identifier.urihttp://hdl.handle.net/10919/35962en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartMcCleary.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectthyroid hormonesen
dc.subjectPCBsen
dc.subjectJapanese quailen
dc.subjecturidinediphosphate-glucuronosyltransferase (UDP-Gen
dc.subjectavian developmenten
dc.titleUridinediphosphate-glucuronosyltransferase (UDP-GT) Ontogeny and PCB Effects in Galliform Birdsen
dc.typeThesisen
thesis.degree.disciplineBiologyen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen
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