Show simple item record

dc.contributor.authorLees, Simon J.en
dc.date.accessioned2014-03-14T20:08:39Zen
dc.date.available2014-03-14T20:08:39Zen
dc.date.issued2003-03-27en
dc.identifier.otheretd-03312003-141236en
dc.identifier.urihttp://hdl.handle.net/10919/26566en
dc.description.abstractIn this investigation, skeletal muscle sarcoplasmic reticulum (SR) was purified from female Sprague Dawley rats (200-250 g). SR samples were subjected to two different biochemical glycogen-extraction protocols. The results suggest that both amylase and removal of EDTA (No-EDTA) from the homogenization and storage buffers reduced the amount of glycogen associated with the SR. Both of these treatments failed to impair SR calcium (Ca2+) handling when assayed under conditions where exogenous ATP was added and utilized for SR Ca2+ transport. In fact, these treatments seemed to cause a small increase in both SR Ca2+-uptake and release rates under these assay conditions. As expected, glycogen phosphorylase content was reduced as a result of glycogen extraction in the presence of amylase, however this was not the case for No-EDTA samples. Interestingly, many other proteins differed in content after glycogen extraction. These treatments resulted in a greater recovery of the sarco(endo)plasmic reticulum Ca2+ adenosine triphosphatase (SERCA) and a substantial loss of glycogen phosphorylase and glycogen debranching enzyme (AGL) in amylase-treated samples. Creatine kinase (CK) and pyruvate kinase (PK) contents were increased as a result of both glycogen-extraction conditions. It was imperative to consider these altered protein contents while analyzing the data and assessing the effects of glycogen extraction on SR Ca2+ handling. After normalizing to SERCA content, only No-EDTA samples had higher adenosine triphosphate (ATP)-supported SR Ca2+-uptake rates compared to control samples. For endogenously synthesized ATP-supported SR Ca2+-uptake experiments, normalizing data to protein content (either CK and SERCA or PK and SERCA) revealed that amylase-treated samples had lower SR Ca2+-uptake rates, compared to control samples. Although not significant, SR Ca2+-uptake rates for No-EDTA samples were also lower than control samples. These data suggest that changes in endogenously supported SR Ca2+-uptake due to glycogen extraction affected the source of ATP synthesis (either PK or CK), the effectiveness of energy utilization for Ca2+ transport (SERCA), or altered the metabolic channeling properties.en
dc.publisherVirginia Techen
dc.relation.haspartSimonLees.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectskeletal muscleen
dc.subjectglycogenen
dc.subjectsarcoplasmic reticulumen
dc.subjectcalcium handlingen
dc.titleGlycogen extraction from skeletal muscle sarcoplasmic reticulum: structural and functional implicationsen
dc.typeDissertationen
dc.contributor.departmentHuman Nutrition, Foods, and Exerciseen
dc.description.degreePh. D.en
thesis.degree.namePh. D.en
thesis.degree.leveldoctoralen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.disciplineHuman Nutrition, Foods, and Exerciseen
dc.contributor.committeechairWilliams, Jay H.en
dc.contributor.committeememberWard, Christopher W.en
dc.contributor.committeememberNewton, William E.en
dc.contributor.committeememberBarbeau, William E.en
dc.contributor.committeememberMoore, David M.en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-03312003-141236/en
dc.date.sdate2003-03-31en
dc.date.rdate2007-04-04en
dc.date.adate2003-04-04en


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record