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ARS Home » Southeast Area » Little Rock, Arkansas » Arkansas Children's Nutrition Center » Research » Publications at this Location » Publication #150524
Title: EFFECTS OF DIETS CONTAINING RICE PROTEIN ISOLATE (RPI) ON GROWTH, PLASMA IGF1, CYP2C11 AND CYP4A1 IN RAT LIVER AT WEANING

Author
item RONIS, MARTIN - UAMS/ACNC
item REEVES, MISTY - ACNC
item HARDY, HOLLY - ACNC
item BADEAUX, JAMIE - ACNC
item DAHL, CHRIS - ACNC
item HARRISON, DAVID - ACNC
item HALEY, RANI - ACNC
item HUMPHREY, LANDON - ACNC
item FERGUSON, MATTHEW - ACNC
item BADGER, THOMAS - UAMS/ACNC

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/28/2003
Publication Date: 6/30/2003
Citation: RONIS, M.J., REEVES, M., HARDY, H., BADEAUX, J., DAHL, C., HARRISON, D., HALEY, R., HUMPHREY, L., FERGUSON, M., BADGER, T.M. EFFECTS OF DIETS CONTAINING RICE PROTEIN ISOLATE (RPI) ON GROWTH, PLASMA IGF1, CYP2C11 AND CYP4A1 IN RAT LIVER AT WEANING. 2003. CD-ROM. Prague, Czech Republic. 13th International Symposium on Cytochromes P450 Biochemistry and Biophysics.

Interpretive Summary: Rice contains a number of chemicals bound to its protein components including vitamin E derivatives, tocotrienols and oryzanols which have been suggested to contribute to health beneficial effects of rice consumption including reductions in cholesterol. In addition, protein isolates from rice are in widespread use in the food industry and have been shown to produce dietary protection against chemical-induced breast cancer in rats. Litters were weaned onto semi-purifed diets, containing either casein (CAS) or rice protein isolate (RPI) as the sole protein source, beginning on post-natal d. 15 until sacrifice at post-natal d. 34. CYP2C11 is a male specific liver enzyme in rats regulated by the male pattern of growth hormone secretion. CYP4A is involved in fatty acid breakdown. Feeding RPI significantly reduced body weight gain in both male and female pups. This was accompanied by significant reductions in plasma IGF1 indicating a suppression or delay in development of the growth hormone axis in these animals. Male growth hormone pattern dependent CYP2C11 mRNA, protein expression and activity were also significantly inhibited in male pups, consistent with effects on growth hormone secretion pattern. Since initial studies on food intake suggest that this was unaffected, the effect of RPI may be due to reduced dietary energy bioavailability or a direct effect of RPI on growth hormone secretion. CYP4A1 mRNA and apoprotein were increased 4-5-fold in pups of both sex suggesting an additional possible stimulatory effect of components of RPI on the metabolism of fatty acids.

Technical Abstract: We fed groups of time-impregnated female Sprague-Dawley rats diets with casein as the sole protein source ad libitum. N = 8-10 male or female pups were weaned onto diets containing either casein (CAS) or rice protein isolate (RPI) as the sole protein source until sacrifice at post-natal d. 34. Feeding RPI reduced body weight gain in both male and female pups (p < 0.05). This was accompanied by reductions in plasma IGF1 concentration (p < 0.05) indicating a suppression or delay in development of the GH/IGF1 axis in these animals. CYP2C11 mRNA and apoprotein expression and testosterone 16'-hydroxylase were also inhibited in male pups (p < 0.05). CYP4A1 mRNA and apoprotein were increased 4-5-fold in pups of both sex suggesting a possible peroxisomal proliferator response to components of RPI.