title: Magnesium deficiency modulates hepatic lipogenesis and apolipoprotein gene expression in the rat.
abstract: The present study was performed to determine the effects of magnesium (Mg) deficiency upon plasma lipoproteins and hepatic apolipoprotein gene expression in the rat. The most obvious effect of Mg-deficiency on plasma lipids is a marked increase in post-prandial triacylglycerol concentration. This increased triglyceridemia persists in fasted rats. Density gradient ultracentrifugation analysis revealed marked alterations in the distribution of plasma lipoproteins in Mg-deficient rats. An increase in triacylglycerol-rich lipoproteins (TGRLP) was associated with a significant increase in plasma apolipoprotein B (apo B) concentration and was accompanied by selective accumulation of apo B-48. A decrease in high-density lipoproteins (HDL) was accompanied by a corresponding decrease in plasma apo E concentration and a concordant decrease in hepatic apo E mRNA abundance and biosynthesis. Hepatic apo B-100 synthesis was reduced by over 75% in Mg-deficient animals despite an increase in hepatic apo B mRNA abundance. However, this change in hepatic apo B gene expression was not associated with alterations in posttranscriptional apo B mRNA editing. These changes in apolipoprotein gene expression were associated with increased hepatic lipogenesis, despite the observation that net triacylglycerol secretion rates were not different between Mg-deficient and control animals. Taken together, the data demonstrate a complex pattern of alterations in hepatic lipid metabolism and apolipoprotein gene expression in the Mg-deficient rat and suggest a defect in the catabolism rather than secretion of TGLRP as the major factor underlying the altered plasma lipoprotein profile.
authors.affiliation: Laboratoire des Maladies Métaboliques, INRA, France.
authors.forename: F
authors.initials: F
authors.lastname: Nassir
authors.forename: A
authors.initials: A
authors.lastname: Mazur
authors.forename: F
authors.initials: F
authors.lastname: Giannoni
authors.forename: E
authors.initials: E
authors.lastname: Gueux
authors.forename: N O
authors.initials: NO
authors.lastname: Davidson
authors.forename: Y
authors.initials: Y
authors.lastname: Rayssiguier
mesh_terms: D000818:Animals; D001053:Apolipoproteins / Q000096:biosynthesis* / Q000097:blood / Q000235:genetics; D015870:Gene Expression; D008074:Lipoproteins / Q000097:blood / Q000737:chemistry; D008099:Liver / Q000378:metabolism*; D008275:Magnesium Deficiency / Q000378:metabolism*; D008297:Male; D017393:RNA Editing; D051381:Rats; D017208:Rats, Wistar; D014280:Triglycerides / Q000737:chemistry / Q000378:metabolism
chemical_list: D001053:Apolipoproteins; D008074:Lipoproteins; D014280:Triglycerides