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ARS Home » Northeast Area » Ithaca, New York » Robert W. Holley Center for Agriculture & Health » Research » Publications at this Location » Publication #102371

Title: IDENTIFYING THE ROLE OF METALLOTHIONEIN (MT) IN ZINC METABOLISM USING KINETIC STUDIES IN MT-KNOCKOUT MICE

Author
item WASTNEY, MERYL - GEORGETOWN UNIV MEDICAL
item House, William

Submitted to: Trace Elements in Man and Animals International Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 6/9/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Metallothionein (Mt) may have a role in regulating zinc (Zn) metabolism. Therefore, Zn kinetics were assessed in control mice and in mice that do not express metallothionein (Mt) form 1 or 2. Female Mt-null (n=48) and control (n=43) mice were fed a diet containing 100 mg Zn/kg. Differences in Zn metabolism due to Mt were determined by comparing tracer distribution among 16 tissues after oral administration of radiozinc. Urine and feces were collected for 2, 4 or 8 d, and mice (n=4 of each strain) were killed at 0.5, 1, 2, 3, 6, and 12 hr and 1, 2, 4, and 8 d. Zn concentration and 65Zn activity were measured in plasma, red blood cells, liver, spleen, kidneys, adrenals, heart, pancreas, lungs, pelt, bone, brain, eyes, reproductive tract, muscle, and six intestinal segments. Mt-null mice compared to controls were heavier and had lower amounts of Zn in liver, reproductive tract and pancreas. More 65Zn entered plasma within 30 min of fthe oral dose and Zn and 65Zn were lower in brain and pancreas of Mt-null mice than in the controls. Mt affects absorption and distribution of Zn to specific tissues in vivo. A compartmental model, applied previously to rats, was used to fit data from all tissues simultaneously. A minimum number of differences were introduced into the model as necessary to account for data in MT-null and control mice. These differences may represent sites where Mt regulates zinc metabolism. The model can be used to determine the degree of difference as well as the pool turnover times and rates of zinc exchange with tissues in Mt-null versus control mice.