Plasma amino acids and excretion of protein end products by mice fed 10 or 40% soybean protein diets with or without dietary 2-acetylaminofluorene or N,N-dinitrosopiperazine.
Studies were conducted with 5- to 8-week-old male and female B6C3F1 mice to determine the influence of two carcinogens, 2-acetylaminofluorene (AAF) and N,N-dinitrosopiperazine (DNP), on plasma amino acid concentrations and on the excretion of lipids and nitrogenous metabolites. The carcinogens, AAF and DNP, were fed at concentrations of 0.25 and 0.05 g/kg of purified diet, respectively. Soybean protein constituted either 10 or 40% of the diet. Nutritional balances were measured over a 7-day period, after 7 days of acclimatization. Females ate less feed, gained less weight during acclimatization and excreted less fecal lipid as a percentage of intake than males. On the average, animals fed 40% protein consumed less total feed than those fed 10% protein. During acclimatization, DNP-fed animals ate and gained significantly less than controls. During week 2 DNP-fed animals gained significantly less than controls, although their feed intake was not significantly different. Fecal lipid excretion as a percentage of intake was significantly lower with carcinogens in the diet. The 40% protein diets increased lipid excretion in total and as a percentage of intake. With the exception of decreasing fecal lipid, AAF caused no consistent changes in feed intake, body weight, nitrogen (N) retention or N excretion. Neither carcinogen significantly influenced total fecal or urinary N, or the relative concentrations of the different forms of urinary N, when expressed as a percentage of N intake. Plasma ammonia rose with AAF feeding and plasma histidine rose with DNP feeding. Plasma concentrations of other amino acids were not changed consistently by either carcinogen. Feeding 40% protein caused a significant rise in plasma branched-chain amino acids, glycine and phenylalanine, and a significant decline in aspartate, threonine, serine, proline, citrulline, lysine and arginine.
D015073:2-Acetylaminofluorene / Q000494:pharmacology*; D000596:Amino Acids / Q000097:blood*; D000597:Amino Acids, Branched-Chain / Q000097:blood; D000818:Animals; D002273:Carcinogens / Q000494:pharmacology*; D004044:Dietary Proteins / Q000378:metabolism*; D005260:Female; D006639:Histidine / Q000097:blood; D008297:Male; D051379:Mice; D009584:Nitrogen / Q000652:urine; D009602:Nitrosamines / Q000494:pharmacology*; D013025:Glycine max
D000596:Amino Acids; D000597:Amino Acids, Branched-Chain; D002273:Carcinogens; D004044:Dietary Proteins; D009602:Nitrosamines; D006639:Histidine; D015073:2-Acetylaminofluorene; C026156:N,N'-dinitrosopiperazine; D009584:Nitrogen