ABSTRACT
Activity of microsomal hydroxylation and conjugation enzymes was studied in the liver of rats that received food concentrate of protein from sunflower groats (SPC) produced in the USSR, and soya protein isolate (SPI) produced by Ralston Purina, USA. SPC consumption during 3 months was attended by elevation of cytochrome-450 content, and activity of microsomal hydroxylation and uridinephosphate-glucuroniltransferase (UDP-GT) in hepatic microsomes, that may evidence the presence in SPC of chemical compounds of natural origin, or chemical modification of the own amino-acid products. SPI did not influence activity of microsomal hydroxylation enzymes, but it raised UDP-GT activity. Both protein products produced no effect on activity of enzymes associated with glutathione metabolism--glutathione-S-transferase and glutathione-reductase in hepatic cytosol. However, SPC and SPI induced a manifold rise in glutathione-peroxidase activity in cytosol of the liver and blood that indicates the presence of the trace element selenium in the products studied.