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Dietary zinc affects the amount of molecular distribution of zinc in endogenous secretions

Conference · · FASEB Journal (Federation of American Societies for Experimental Biology); (United States)
OSTI ID:5174724
;  [1]
  1. Dept. of Agriculture, Grand Forks, ND (United States)

Long-Evans rats were used to examine the effect of dietary Zn on Zn secreted into endogenous secretions. Animals were fed diets containing 8, 20, or 60 mg Zn per kg diet for six weeks. Rats were then anesthetized, opened at midline and polyethylene cannulas were inserted into the common duct or bile duct for collection of bile/pancreatic fluid or pure bile. Additionally, some rats were injected with 65-Zn 48h prior to cannulation. Secretions were chromatographed on G-75 Sephadex equilibrated with 0.1 M Tris, pH 8.0. Fractions were collected and analyzed for Zn and 65-Zn. More Zn and 65-Zn were found in the pancreatic/biliary secretions than in pure bile. The amount of 65-Zn in bile/pancreatic secretions varied with diet. Zinc and 65-Zn from pancreatic/biliary secretions were found in low and high molecular weight fractions with the greatest amount contained in the high molecular weight fraction. The molecular weight of ligands binding 65-Zn was not affected by diet; however, less 65-Zn was associated with the low molecular weight fraction in rats fed 8 ppm than in animals fed 60 ppm Zn. Non-radioactive bile/pancreatic fluid was incubated with 65-Zn and also chromatographed. Secretions labeled in this way contained most 65-Zn in the low molecular weight fraction. These results suggest that, within a physiological range, the secretion of endogenous Zn mirrors Zn intake. A low molecular weight Zn ligand in bile/pancreatic fluid apparently is most responsive to changes in dietary Zn. These data also suggest that 65-Zn added exogenously does not completely exchange with endogenously secreted Zn.

OSTI ID:
5174724
Report Number(s):
CONF-9104107--
Journal Information:
FASEB Journal (Federation of American Societies for Experimental Biology); (United States), Journal Name: FASEB Journal (Federation of American Societies for Experimental Biology); (United States) Vol. 5:5; ISSN FAJOE; ISSN 0892-6638
Country of Publication:
United States
Language:
English