Dietaiy protein modifies oxidized cholesterol-induced alterations of linoleic acid and cholesterol metabolism in rats

Kyoichi Osada, Takehiro Kodama, Kaori Minehira, Koji Yamada, Michihiro Sugano

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

Effects of dietary protein on oxidized cholesterol-induced alterations in linoleic acid and cholesterol metabolism were studied in 4-wk-old male Sprague-Dawley rats, using casein and soybean protein as dietary protein sources. The rats were fed one of the two proteins in cholesterol-free, 0.3% cholesterol or 0.3% oxidized cholesterol mixture diets using a pair-feeding protocol for 3 wk. In the soybean protein-fed group, rats fed oxidized cholesterol did not have lower activity of liver microsomal Δ6 desaturase, the rate-limiting enzyme in the metabolism of linoleic acid to arachidonic acid, compared with rats fed cholesterol-free diet, whereas in the casein-fed group the desaturase activity was significantly greater in rats fed oxidized cholesterol than in those fed cholesterol-free diet. This was in contrast to a significant reduction in liver microsomal Δ6 desaturase activity by cholesterol, irrespective of protein source. In general, these changes were reflected in the desaturation indices of liver phospholipids. Furthermore, soybean protein significantly increased the fecal excretion of neutral and acidic steroids and tended to reduce (P = 0.082) the accumulation of oxidized cholesterols in the liver. Thus, soybean protein partly modified some of the undesirable effects of oxidized cholesterol through its hypocholesterolemic effect and possibly through the modulation of hepatic Δ6 desaturase activity.

Original languageEnglish
Pages (from-to)1635-1643
Number of pages9
JournalJournal of Nutrition
Volume126
Issue number6
DOIs
Publication statusPublished - Jun 1996

Keywords

  • Casein
  • Oxidized cholesterol
  • Rats
  • Soybean protein
  • Δ6 desaturase

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