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ARS Home » Southeast Area » Little Rock, Arkansas » Microbiome and Metabolism Research Unit » Research » Publications at this Location » Publication #151336
Title: LIFETIME FEEDING OF WHEY PROTEIN-BASED DIET SUPPRESSES HEPATIC GST-PI MRNA EXPRESSION IN FEMALE RATS

Author
item SANDERS, YAN - UAMS
item BADGER, THOMAS - 6251-10-00
item SIMMEN, FRANK - UAMS

Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: 1/10/2003
Publication Date: 3/17/2003
Citation: SANDERS, Y., BADGER, T.M., SIMMEN, F.A. Lifetime feeding of whey protein-based diet suppresses hepatic GST-pi mRNA expression in female rats. JOURNAL OF FEDERATION OF AMERICAN SOCIETIES FOR EXPERIMENTAL BIOLOGY. 2003. v. 17(5). p. A1162. Abstract No. 713.7.

Interpretive Summary: The ACNC has is interested in dietary factors that prevent diseases, and especially interested in determining if there will be protection against diseases that typically occur later in life (i.e. breast cancer) by early dietary exposure (either in utero or in infancy). We have focused on proteins that are in infant formula (casein, whey and soy). We found that rats fed diets made with whey protein isolate or soy protein isolate leads to their increased protection against various types of cancers (breast and colon). We have studied how whey and soy proteins affect the activity of certain genes that are expressed in the liver of the rat in order to understand how these proteins may act against cancer in humans. In this study, we found that a particular gene, named GST-pi, is lowered in its activity in livers of rats fed whey protein in the diet. Since this gene is generally more active in cancer tissues, the lowering of its activity by feeding of whey may be part of the cancer protection of this diet. Our findings suggest that the use of whey protein in diets may be beneficial in protection against liver cancer and that this involves the GST-pi gene. Our future research will determine whether there is a connection between these finding and cancer risk. In addition, our research will focus upon very early dietary effects in fetal and early infant life.

Technical Abstract: Feeding of soy and whey-based diets to rodent models confers protection, relative to casein-based diet, against carcinogenesis. Here, we have used the female Sprague Dawley rat (age: postnatal day 51) subjected to lifetime feeding of casein (n=9), whey protein (n=7) or soy protein-based (n=9) diets, to establish suitable conditions for hepatic gene expression analysis using real-time quantitative RT-PCR. Female offspring of mothers fed the individual diet during gestation and lactation were weaned onto the same diet. Effects of diet on mRNA abundance of five mRNAs were examined: IGFBP-1, a low molecular weight serum IGF carrier which is highly responsive to nutritional factors; GST-pi, a phase II detoxification system enzyme that is a marker of pre-neoplastic lesions during hepatocarcinogenesis; the anti-apoptotic gene Bcl-2; and two potential normalization genes, ß-actin and cyclophilin A. No dietary effects were noted on cyclophilin A mRNA abundance; by contrast, ß-actin mRNA abundance was increased in the whey group. Using cyclophilin A mRNA as reference, ß-actin, IGFBP-1 and Bcl-2 mRNA levels did not differ among groups. By contrast, GST-pi mRNA expression was significantly depressed by approximately 50% in the whey vs. the other groups (P<0.01). Results suggest that GST-pi might serve as a useful marker for dietary modulation of precancerous state in the liver, in contrast to other GST family members. Supported by USDA ARS CRIS 6251-51000-002-06S.