Age- and sex-related differences in nuclear lipid content and nucleoside triphosphatase activity in the JCR:LA-cp corpulent rat

Michael P. Czubryt, James C. Russell, John Sarantopoulos, James S.C. Gilchrist, Grant N. Pierce

Research output: Contribution to journalArticle

Abstract

The putative role of the nuclear nucleoside triphosphatase (NTPase) is to provide energy to the nuclear pore complex for poly A(+) mRNA export. Previous work has demonstrated that liver nuclear NTPase activity is greater in 6 month old corpulent (cp/cp) female JCR:LA rats, a hyperlipidemic rat model, compared to lean (+/?) animals. This increase appeared to be related to increases in nuclear membrane cholesterol content. The current study extended these initial data to compare NTPase activity as a function of age and sex in isolated JCR:LA-cp rat liver nuclei, to further test the hypothesis that nuclear membrane cholesterol may modulate NTPase activity. NTPase activity was increased in cp/cp female animals compared to +/? females at all ages studied, with V(max) values increased by 60-176%. Membrane integrity of cp/cp female nuclei was reduced compared to +/? female nuclei. Nuclear membrane cholesterol levels increased linearly with age by 50, 150 and 250% in 3, 6 and 9 month old cp/cp females over leans. In contrast, nuclei from cp/cp males exhibited only minor, isolated changes in NTPase activity. Furthermore, there were no significant changes in nuclear cholesterol content or membrane integrity in the less hyperlipidemic male animals at any age. These data suggest that altered lipid metabolism may lead to changes in nuclear membrane structure, which in turn may alter NTPase activity and functioning of the nuclear pore complex.

Original languageEnglish (US)
Pages (from-to)327-335
Number of pages9
JournalMolecular and Cellular Biochemistry
Volume176
Issue number1-2
DOIs
StatePublished - Nov 28 1997
Externally publishedYes

Keywords

  • Hypercholesterolemia
  • Nuclear membrane
  • Nuclear pore complex
  • Nucleocytoplasmic transport
  • Nucleoside triphosphatase

ASJC Scopus subject areas

  • Molecular Biology
  • Clinical Biochemistry
  • Cell Biology

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