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Postprandial leucine and insulin responses and toxicological effects of a novel whey protein hydrolysate-based supplement in rats


The purpose of this study was: aim 1) compare insulin and leucine serum responses after feeding a novel hydrolyzed whey protein (WPH)-based supplement versus a whey protein isolate (WPI) in rats during the post-absorptive state, and aim 2) to perform toxicological analysis on rats that were fed different doses of the novel WPH-based supplement over a 30-day period.


In male Wistar rats (~250 g, n = 40), serum insulin and leucine concentrations were quantified up to 120 min after one human equivalent dose of a WPI or the WPH-based supplement. In a second group of rats (~250 g, n = 20), we examined serum/blood and liver/kidney histopathological markers after 30 days of feeding low (1human equivalent dose), medium (3 doses) and high (6 doses) amounts of the WPH-based supplement.


In aim 1, leucine levels were significantly higher at 15 min after WPH vs. WPI ingestion (p = 0.04) followed by higher insulin concentrations at 60 min (p = 0.002). In aim 2, liver and kidney histopathology/toxicology markers were not different 30 days after feeding with low, medium, high dose WPH-based supplementation or water only. There were no between-group differences in body fat or lean mass or circulating clinical chemistry markers following the 30-day feeding intervention in aim 2.


In comparison to WPI, acute ingestion of a novel WPH-based supplement resulted in a higher transient leucine response with a sequential increase in insulin. Furthermore, chronic ingestion of the tested whey protein hydrolysate supplement appears safe.


This study was funded in full by Scivation, Inc. The authors disclose no financial consulting benefits from Scivation, Inc. or any other companies. Serum leucine analysis was conducted at the Washington University Biomedical Mass Spectrometry Research Resource (supported by NIH Grants RR000954, DK020579 & DK056341). We also graciously acknowledge Charles Wiedmeyer at RADIL for his analyses of serum and blood samples as well as Dr. Chris Lockwood, Dr. Kevin Yarasheski, Joe Company, Jacob Brown, Leigh Gilpin and Dr. Robert Backus for their intellectual insight during the completion of experiments.

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Correspondence to Michael D Roberts.

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Open Access This article is published under license to BioMed Central Ltd. This is an Open Access article is distributed under the terms of the Creative Commons Attribution License ( ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Toedebusch, R.G., Childs, T.E., Hamilton, S.R. et al. Postprandial leucine and insulin responses and toxicological effects of a novel whey protein hydrolysate-based supplement in rats. J Int Soc Sports Nutr 9 (Suppl 1), P30 (2012).

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