Proteinuria, not altered albumin metabolism, affects hyperlipidemia in the nephrotic rat

R. William Davies, Ilona Staprans, Florence N. Hutchison, George Kaysen

Research output: Contribution to journalArticle

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Abstract

It has been established previously that nephrotic hyperlipidemia is characterized by both an increase in lipid synthesis and a defect in removal of lipoproteins. The relationship between these defects and altered albumin metabolism is uncertain. One hypothesis is that hepatic lipogenesis increases in parallel with albumin synthesis. To test this hypothesis, albumin synthesis was increased in nephrotic rats fed an 8.5% protein diet (LPN) by increasing dietary protein to 40% (HPN). Proteinuria was modulated in half of the rats fed 40% protein by enalapril (HPE). Albumin synthesis was the same in both HPN and HPE, but proteinuria was reduced in HPE compared to HPN, and so were serum cholesterol and triglycerides (TG). To examine the effect of serum albumin on lipid clearance in the absence of proteinuria, plasma clearance of chylomicrons (CM) and VLDL was measured in Nagase analbuminemic rats (NAR) and found to be no different than in normal SD rats. When proteinuria was induced in NAR and in SD rats, a severe and identical defect in both CM and VLDL clearance was acquired in both groups and blood lipid levels were increased to a similar degree in both groups. Neither hyperlipidemia nor defective removal of lipoproteins from the circulation are linked to albumin synthesis or serum albumin concentration but result, at least in part, from proteinuria. Postheparin lipoprotein lipase (LPL) activity was reduced slightly in nephrotic animals compared to nonnephrotic controls, but the most striking finding was a highly significant decrease in postheparin LPL activity in normal NAR compared to SD rats (P < 0.001), suggesting that reduced LPL activity is not responsible for reduced clearance of CM and VLDL in nephrotic rats.

Original languageEnglish (US)
Pages (from-to)600-605
Number of pages6
JournalJournal of Clinical Investigation
Volume86
Issue number2
StatePublished - Aug 1990

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Hyperlipidemias
Proteinuria
Albumins
Chylomicrons
Acetylglucosaminidase
Lipoprotein Lipase
Lipids
Serum Albumin
Lipoproteins
Lipogenesis
Enalapril
Dietary Proteins
Blood Group Antigens
Triglycerides
Proteins
Cholesterol
Diet
Liver
Serum

Keywords

  • Analbuminemia
  • Chylomicrons
  • Lipoprotein lipase
  • Nephrosis
  • VLDL

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Proteinuria, not altered albumin metabolism, affects hyperlipidemia in the nephrotic rat. / Davies, R. William; Staprans, Ilona; Hutchison, Florence N.; Kaysen, George.

In: Journal of Clinical Investigation, Vol. 86, No. 2, 08.1990, p. 600-605.

Research output: Contribution to journalArticle

Davies, R. William ; Staprans, Ilona ; Hutchison, Florence N. ; Kaysen, George. / Proteinuria, not altered albumin metabolism, affects hyperlipidemia in the nephrotic rat. In: Journal of Clinical Investigation. 1990 ; Vol. 86, No. 2. pp. 600-605.
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