British Journal of Nutrition

Metabolism and Metabolic Studies

Refeeding with a high-protein diet after a 48 h fast causes acute hepatocellular injury in mice

Motoko Oaradaa1 c1, Tsuyoshi Tsuzukia2, Takeshi Nikawaa3, Shohei Kohnoa3, Katsuya Hirasakaa3 and Tohru Gonoia1

a1 Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba 260-8673, Japan

a2 Laboratory of Food and Biomolecular Science, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan

a3 Department of Nutrition, Tokushima University School of Medicine, Tokushima 770-8503, Japan

Abstract

Elucidating the effects of refeeding a high-protein diet after fasting on disease development is of interest in relation to excessive protein ingestion and irregular eating habits in developed countries. The objective of the present study was to address the hepatic effects of refeeding a high-protein diet after fasting. Mice were fasted for 48 h and then refed with a test diet containing 3, 15, 35, 40, 45 or 50 % casein. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities and liver immediate-early gene expression levels were sequentially measured for the first 24 h after initiation of refeeding. Refeeding with a 50 % casein diet after 48 h of fasting led to a rapid (within 2–3 h) and abnormal elevation in serum ALT (P = 0·006) and AST (P = 0·001) activities and a marked increase in liver Finkel-Biskis-Jinkins (FBJ) osteosarcoma oncogene (P = 0·007) and nuclear receptor subfamily 4, group A, member 1 (P = 0·002) mRNA levels. In contrast, refeeding of the 3, 15 or 35 % casein diets produced no substantial increases in serum ALT and AST activities in mice. Refeeding of 40, 45 or 50 % casein increased serum ALT and AST activities in proportion to this dietary casein content. In mice refed the 3, 15 or 35, but not 50 %, casein diets, liver heat shock protein 72 transcript levels greatly increased. We conclude from these data that the consumption of a high-protein diet after fasting causes acute hepatocellular injury in healthy animals, and propose that careful attention should be paid to the use of such diets.

(Received January 17 2011)

(Revised May 25 2011)

(Accepted July 13 2011)

(Online publication September 09 2011)

Correspondence:

c1 Corresponding author: M. Oarada, fax +81 43 226 2486, email motoko.o@faculty.chiba-u.jp

Footnotes

Abbreviations: ALT, alanine aminotransferase; AST, aspartate aminotransferase; Btg2, B-cell translocation gene 2, anti-proliferative; c-fos, FBJ osteosarcoma oncogene; Crp, C-reactive protein; Gadd45g, growth arrest and DNA-damage-inducible 45 gamma; Hsp72, heat shock protein 1A; nur77, nuclear receptor subfamily 4, group A, member 1; TBARS, thiobarbituric acid-reactive substance; Ung, uracil-DNA glycosylase

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