Specially processed cereals diet increases plasma levels of active antisecretory factor and up-regulates rat hepatic glutathione S-transferase mu

Objective: Antisecretory factor (AF) inhibits pathologic fluid secretion and inflammation. AF is expressed in most tissues and is secreted into the blood. Challenge with bacterial enterotoxins increases AF activity. The plasma level of active AF is also increased after intake of certain food constituents, such as specially processed cereals, SPC. The exact molecular events that mediate these responses have remained obscure. The objective of this study was to investigate changes in protein expression in liver after SPC diet. Methods: Rats were fed SPC or standard rodent diet for 18 d. The induction of AF in plasma was tested by ELISA. Changes in the liver proteome were analyzed by using 2D DICE and LC-MS/MS. Further characterizations were done with Western blot and immunohistochemistry studies. Results: The AF activity was increased after intake of SPC. Equivalent to recombinant AF, 6.6 +/- 1.09 ng/well could be detected in control plasma compared to 26 +/- 5.73 ng/well in plasma after SPC treatment. We found that the protein level of glutathione S-transferase mu (GST mu) was significantly up-regulated 1.2-fold in rat liver after stimulation with SPC (wheat). The result was further confirmed by Western blot analysis. Immunohistochemistry showed staining for GST mu1 and AF preferentially in the central parts of the liver lobuli. Conclusion: Given the known role of GST mu1 in inducing defense, our results suggest that SPC-induced GST mu1 up-regulation can contribute to the positive clinical effects seen by SPC treatment. (C) 2011 Elsevier Inc. All rights reserved.