Relationship of /sup 65/Zn absorption kinetics to intestinal metallothionein in rats: effects of zinc depletion and fasting

Journal Article · Thu Mar 31 23:00:00 EST 1988 · J. Nutr.; (United States)

OSTI ID:6936299

Hoadley, J E; Leinart, A S; Cousins, R J

Intestinal 65Zn transport and metallothionein levels were examined in rats fed zinc-adequate and zinc-deficient diets and in rats subjected to an overnight fast. 65Zn uptake by intestines perfused with 1.5 microM 65Zn was greater in both zinc-deficient and fasted groups than in the control group. Mucosal retention of 65Zn was also greater in the zinc-deficient group but not in the fasted group. The greater 65Zn uptake in the fasted group was associated with a compartment that readily released 65Zn back into the lumen. Kinetic analysis of the rate of 65Zn transfer to the vascular space (absorption) showed that 65Zn absorption involved approximately 3% of mucosal 65Zn in a 40-min perfusion period. The half-life (t1/2) of this mucosal 65Zn rapid transport pool corresponded directly to changes in intestinal metallothionein levels. Both metallothionein and t1/2 were higher in the fasted group and lower in the zinc-deficient group than in controls. While the rate of 65Zn transport from this rapid transport pool decreased with increasing metallothionein level, the predicted pool size increased when the metallothionein level was elevated by fasting. These results indicate that the rate of zinc absorption is inversely related to intestinal metallothionein levels, but the portion of mucosal 65Zn available for absorption is directly related to intestinal metallothionein.

• Research Organization: Univ. of Florida, Gainesville (USA)
• OSTI ID: 6936299
• Journal Information: J. Nutr.; (United States), Journal Name: J. Nutr.; (United States) Vol. 118:4; ISSN JONUA
• Country of Publication: United States
• Language: English

Related Subjects

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560300* -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ABSORPTION
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BIOLOGICAL HALF-LIFE
BIOSYNTHESIS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
EVEN-ODD NUCLEI
FASTING
INTERMEDIATE MASS NUCLEI
INTESTINAL ABSORPTION
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
MEMBRANE TRANSPORT
METALLOPROTEINS
METALLOTHIONEIN
METALS
NUCLEI
NUTRITIONAL DEFICIENCY
ORAL ADMINISTRATION
ORGANIC COMPOUNDS
PROTEINS
RADIOISOTOPES
RATS
RETENTION
RODENTS
SYNTHESIS
TRACER TECHNIQUES
UPTAKE
VERTEBRATES
ZINC
ZINC 65
ZINC ISOTOPES