Zinc uptake into endothelial cells involves a carrier mediated component
- USDA-ARS Human Nutrition Center, Grand Forks, ND (United States)
The mechanism of zinc (Zn) uptake by endothelial cells was examined. Bovine pulmonary endothelial cells were grown to a confluent monolayer in T-25 flasks with minimum essential medium (MEM) containing 10% fetal bovine serum. Zn uptake was studied by replacing the growth medium with experimental media of MEM, 14% EDTA dialyzed serum, and 250 nCi {sup 65}Zn/mL. The transport mechanism was studied by manipulating the composition of the experimental media and measuring the accumulation of {sup 65}Zn by the cells during a 10 min incubation period at 37C, 90% relative humidity, and 5% CO{sub 2}. The rate of Zn uptake increased as the Zn concentration in the media increased from 1 to 26 {mu}M. The data were described by a rectangular hyperbola with V{sub max} = 27.2 {plus minus} 0.84 pmoles Zn and K{sub m} = 4.1 {plus minus} 0.46 {mu}M Zn. The mechanism was studied further with 6 {mu}M added Zn (ZnCl{sub 2}) in the experimental media. Zn uptake was temperature dependent; the rate was less than 6C than at 24C, which was less than at 33C. The Zn uptake rate was reduced by the metabolic inhibitors iodoacetate, sodium fluoride, and N-ethylmaleimide. Cadmium competitively inhibited Zn uptake; copper and manganese had no effect. Increasing the concentration of albumin tin the media reduced the Zn uptake rate over the range from 0 to 40 {mu}M albumin in the media reduced the Zn uptake rate over the range from 0 to 40 {mu}M albumin, but not at 50 {mu}M albumin, with 10 {mu}M Zn. The addition of Zn binding ligands decreased the Zn uptake rate in the absence of serum, but increased the rate when serum was present. These results demonstrate that Zn uptake into endothelial cells is facilitated by a transporter possessing a recognition site that is saturable and at least partially energy dependent. Additionally, the uptake rate apparently is influenced by the ligand to which Zn is bound in the extracellular fluid.
- OSTI ID:
- 5215221
- Report Number(s):
- CONF-9104107-; CODEN: FAJOE
- Journal Information:
- FASEB Journal (Federation of American Societies for Experimental Biology); (United States), Vol. 5:5; Conference: 75. annual meeting of the Federation of American Societies for Experimental Biology (FASEB), Atlanta, GA (United States), 21-25 Apr 1991; ISSN 0892-6638
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CADMIUM
BIOLOGICAL EFFECTS
COPPER
MANGANESE
ZINC
MEMBRANE TRANSPORT
ALBUMINS
CATTLE
EDTA
ENDOTHELIUM
INHIBITION
LUNGS
METABOLISM
TEMPERATURE DEPENDENCE
TRACER TECHNIQUES
UPTAKE
ZINC 65
AMINO ACIDS
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BODY
CARBOXYLIC ACIDS
CHELATING AGENTS
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
EVEN-ODD NUCLEI
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
METALS
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RADIOISOTOPES
RESPIRATORY SYSTEM
RUMINANTS
TISSUES
TRANSITION ELEMENTS
VERTEBRATES
ZINC ISOTOPES
560300* - Chemicals Metabolism & Toxicology