Uptake of lead by human red blood cells and intracellular distribution.
Kitasato Arch Exp Med
; 63(4): 15-23, 1990 Dec.
Article
in En
| MEDLINE
| ID: mdl-2130186
ABSTRACT
Lead added to plasma was rapidly incorporated into suspended human red blood cells at 37 degrees C. The rate of lead uptake into the cells reached a maximum of 35 micrograms (0.17 mumole)/10(10) cells/h. The rate of lead uptake with resealed ghosts was comparable to that of intact cells. These findings indicate that the transport of lead across the erythrocyte membrane is, energy-independent, carrier-mediated passive transport, which confirms the conclusion of Simons. On the other hand, little release of incorporated lead from the cells in lead-free plasma was observed. Some 98% of intracellular lead was in cytoplasm, mostly in protein-bound form, and only 2% was in the membrane fraction. When red blood cells were incubated in plasma containing lead at about 10 mg/dl concentration for 24 hours at 37 degrees C, no progressive accumulation of lead and protein in the membrane fraction was observed. Thus, lead-protein complexes in cytosol are unlikely to associate with membranes. Human haemoglobin had forty-five binding sites for lead with the dissociation constant of 0.5 x 10(-6) M. The binding of lead to oxyhaemoglobin did not show any effect on the iron atom in the heme.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Erythrocyte Membrane
/
Erythrocytes
/
Lead
Limits:
Humans
Language:
En
Journal:
Kitasato Arch Exp Med
Year:
1990
Document type:
Article
Affiliation country:
Japón