title: Aging effects on hepatic NADPH cytochrome P450 reductase, CYP2B1&2, and polymeric immunoglobulin receptor mRNAs in male Fischer 344 rats.
abstract: Aging perturbs the expression of many liver proteins, but the mechanisms remain unresolved. Expression of hepatic NADPH cytochrome P450 reductase, phenobarbital-induced CYP2B1&2, and the polymeric immunoglobulin receptor (pIgR) decline as a function of aging. We examined the effect of aging on the expression of the mRNA transcripts of these proteins, as well as those of alpha 2u-globulin and beta-actin in male F344 rats. Despite age-related losses in the expression of P450 reductase and plasma membrane-bound pIgR in the rat liver (approximately 30-50%), aging is is accompanied by 1) no change and 2) a modest decline (< 20%) in their respective mRNA steady state levels. On the other hand, the expression of phenobarbital-induced microsomal CYP2B1&2 and the steady state level of its mRNA exhibit parallel age-dependent shifts. The mRNA transcript for alpha 2u-globulin declines between maturity and old age, whereas the beta-actin mRNA level remains unchanged. These preliminary data are consistent with previous studies which suggest that aging may perturb hepatic CYP2B1&2 and alpha 2u-globulin at the transcriptional level, whereas changes in the expression of P450 reductase and pIgR may reflect posttranscriptional modifications.
authors.affiliation: Cell Biology & Aging Section, Department of Veterans Affairs Medical Center, San Francisco, California 94121.
authors.forename: R L
authors.initials: RL
authors.lastname: van Bezooijen
authors.forename: R K
authors.initials: RK
authors.lastname: Wang
authors.forename: M C
authors.initials: MC
authors.lastname: Lechner
authors.forename: D L
authors.initials: DL
authors.lastname: Schmucker
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D000375:Aging / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D000510:Alpha-Globulins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D019362:Cytochrome P-450 CYP2B1; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism; D008099:Liver / Q000276:immunology / Q000378:metabolism*; D008297:Male; D009251:NADPH-Ferrihemoprotein Reductase / Q000235:genetics / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D011971:Receptors, Immunologic; D012635:Secretory Component / Q000235:genetics / Q000378:metabolism
chemical_list: D000199:Actins; D000510:Alpha-Globulins; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D012635:Secretory Component; C013803:alpha 2u globulin; D003577:Cytochrome P-450 Enzyme System; D010088:Oxidoreductases; D019362:Cytochrome P-450 CYP2B1; D009251:NADPH-Ferrihemoprotein Reductase