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Title: /sup 54/Mn absorption and excretion in rats fed soy protein and casein diets

Rats were fed diets containing either soy protein or casein and different levels of manganese, methionine, phytic acid, or arginine for 7 days and then fed test meals labeled with 2 microCi of 54Mn after an overnight fast. Retention of 54Mn in each rat was measured every other day for 21 days using a whole-body counter. Liver manganese was higher (P less than 0.0001) in soy protein-fed rats (8.8 micrograms/g) than in casein-fed rats (5.2 micrograms/g); manganese superoxide dismutase activity also was higher in soy protein-fed rats than in casein-fed rats (P less than 0.01). There was a significant interaction between manganese and protein which affected manganese absorption and biologic half-life of 54Mn. In a second experiment, rats fed soy protein-test meals retained more 54Mn (P less than 0.001) than casein-fed rats. Liver manganese (8.3 micrograms/g) in the soy protein group was also higher than that (5.7 micrograms/g) in the casein group (P less than 0.0001), but manganese superoxide dismutase activity was unaffected by protein. Supplementation with methionine increased 54Mn retention from both soy and casein diets (P less than 0.06); activity of manganese superoxide dismutase increased (P less than 0.05) but liver manganese did not change. The addition ofmore » arginine to casein diets had little effect on manganese bioavailability. Phytic acid affected neither manganese absorption nor biologic half-life in two experiments, but it depressed liver manganese in one experiment. These results suggest that neither arginine nor phytic acid was the component in soy protein which made manganese more available from soy protein diets than casein diets.« less
Authors:
;
Publication Date:
OSTI Identifier:
6401138
Resource Type:
Journal Article
Resource Relation:
Journal Name: Proc. Soc. Exp. Biol. Med.; (United States); Journal Volume: 190:2
Research Org:
United States Department of Agriculture, Grand Forks, ND (USA)
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; 59 BASIC BIOLOGICAL SCIENCES; MANGANESE; METABOLISM; PROTEINS; BIOLOGICAL EFFECTS; SUPEROXIDE DISMUTASE; ENZYME ACTIVITY; ARGININE; BIOLOGICAL AVAILABILITY; BIOLOGICAL HALF-LIFE; CASEIN; LIVER; MANGANESE 54; METHIONINE; PHYTIC ACID; RATS; TRACER TECHNIQUES; WHOLE-BODY COUNTING; AMINO ACIDS; ANIMALS; BETA DECAY RADIOISOTOPES; BODY; CARBOXYLIC ACIDS; COUNTING TECHNIQUES; DAYS LIVING RADIOISOTOPES; DIGESTIVE SYSTEM; DRUGS; ELECTRON CAPTURE RADIOISOTOPES; ELEMENTS; ENZYMES; ESTERS; GLANDS; INTERMEDIATE MASS NUCLEI; ISOTOPE APPLICATIONS; ISOTOPES; LIPOTROPIC FACTORS; MAMMALS; MANGANESE ISOTOPES; METALS; NUCLEI; ODD-ODD NUCLEI; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC PHOSPHORUS COMPOUNDS; ORGANIC SULFUR COMPOUNDS; ORGANS; OXIDOREDUCTASES; PHOSPHORIC ACID ESTERS; RADIOISOTOPES; RODENTS; TRANSITION ELEMENTS; VERTEBRATES 560300* -- Chemicals Metabolism & Toxicology; 550501 -- Metabolism-- Tracer Techniques