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This Article Full Text Full Text (PDF) All Versions of this Article: 293/6/E1580    most recent 00169.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Afolabi, P. R. Articles by Elia, M. Search for Related Content PubMed PubMed Citation Articles by Afolabi, P. R. Articles by Elia, M.

The effect of total starvation and very low energy diet in lean men on kinetics of whole body protein and five hepatic secretory proteins

¹Institute of Human Nutrition, University of Southampton, Southampton General Hospital, Southampton, United Kingdom; ²Department of Pediatrics, Childrens' Nutrition Research Center, Baylor College of Medicine, Houston, Texas; ³Rowett Research Institute, Bucksburn, Aberdeen, United Kingdom; ⁴School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Dublin, United Kingdom

Submitted 15 March 2007 ; accepted in final form 9 September 2007

It is unclear whether the rate of weight loss, independent of magnitude, affects whole body protein metabolism and the synthesis and plasma concentrations of specific hepatic secretory proteins. We examined 1) whether lean men losing weight rapidly (starvation) show greater changes in whole body protein kinetics, synthesis, and circulating concentrations of selected hepatic secretory proteins than those losing the same amount of weight more slowly [very low energy diet (VLED)]; and 2) whether plasma concentrations and synthetic rates of these proteins are related. Whole body protein kinetics were measured using [1-¹³C]leucine in 11 lean men (6 starvation, 5 VLED). Fractional and absolute synthetic rates of HDL-apolipoprotein A1 (apoA1), retinol binding protein, transthyretin, ₁-antitrypsin (₁-AT), and transferrin were measured using a prime-constant intravenous infusion of [¹³C₂]glycine. Compared with VLED group, the starvation group showed greater increases (at a 5% weight loss) in whole body protein oxidation (P < 0.05); fractional synthetic rates of HDL-apoA1 (25.3 vs. –1.52%; P = 0.003) and retinol binding protein (30.6 vs. 7.1%; P = 0.007); absolute synthetic rates of HDL-apoA1 (7.1 vs. –3.8 mg·kg^–1·day^–1; P = 0.003) and ₁-AT (17.8 vs. 3.6 mg·kg^–1·day^–1; P = 0.02); and plasma concentration of ₁-AT (P = 0.025). Relationships between synthetic rates and plasma concentrations varied between the secreted proteins. It is concluded that synthetic rates of hepatic secreted proteins in lean men are more closely related to the rate than the magnitude of weight loss. Changes in concentration of these secreted proteins can occur independently of changes in synthetic rates, and vice versa.

protein turnover; plasma proteins; very low energy diet