Studies on intestinal copper and zinc absorption in the rat
An attempt is made to examine the interactions zinc and copper undergo at the absorptive level in the rat. In addition, the kinetics of zinc transport by rat intestinal basolateral membrane vesicles are described. The influence copper and zinc exert on each other's absorption was studied using the isolated, vascularly and luminally perfused rat intestine system. Rats were fed one of nine diets for one week, each with a different copper and zinc concentration representing low, adequate and high dietary concentrations (1-36 mg/kg Cu/sup 2 +/ and 5-180 mg/kg Zn/sup 2 +/). Experiments to describe zinc transport out of intestinal cells were carried out using a membrane fraction enriched with basolateral membrane vesicles (BLMV). Initial rates of /sup 65/Zn/sup 2 +/ uptake (extravesicular Zn/sup 2 +/ concentrations of 5 ..mu..M to 625 ..mu..M) with BLMV from zinc-adequate and zinc-deficient rats fit Michaelis-Menten saturation kinetics indicating a carrier-mediated transport process. The Km and Jmax were not significantly changed by dietary zinc status. SDS-PAGE of BLMV from rats of different zinc status did not show differences in the number of abundance of protein bands. Na/sup +/ did not alter /sup 65/Zn/sup 2 +/ uptake. ATP caused a reduction in /sup 65/Zn/sup 2 +/ uptake due to complex formation with zinc ions thereby decreasing the amount of zinc available for transport.
- Research Organization:
- Rutgers--the State Univ., New Brunswick, NJ (USA)
- OSTI ID:
- 5151001
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ABSORPTION
ANIMALS
ATP
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BODY
CATIONS
CHARGED PARTICLES
COPPER
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
EVEN-ODD NUCLEI
INTERMEDIATE MASS NUCLEI
INTESTINAL ABSORPTION
IONS
ISOTOPES
KINETICS
MAMMALS
MEMBRANE TRANSPORT
METALS
NUCLEI
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANS
PERFUSED ORGANS
RADIOISOTOPES
RATS
REACTION KINETICS
RODENTS
TRANSITION ELEMENTS
UPTAKE
VERTEBRATES
ZINC
ZINC 65
ZINC ISOTOPES