Expression of haemopexin receptors by cultured human cytotrophoblast
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The expression of cell-surface haemopexin (Hx) receptors on human cytotrophoblasts was assessed by using four different Hx species purified from plasma: human Hx isolated by wheatgerm-affinity chromatography, human Hx isolated by haem-agarose-affinity chromatography and rabbit and rat Hx, also isolated by haem-agarose-affinity chromatography. About 3500-7000 high-affinity (Kd 0.34-0.85 nM) receptors per cell were measured by Scatchard-type analysis at 4 degrees C using human (species obtained by both methods) or rabbit 125I-labelled haem-Hx. Measured simultaneously, transferrin receptor number and affinity were 40,000/cell and 0.83 nM respectively. In contrast with transferrin receptors, the number of Hx receptors did not increase during 24 h in cytotrophoblast culture. Rat Hx showed no specific binding to human Hx receptors in cytotrophoblast cultures.
- Comparative Study
- Research Support, Non-U.S. Gov't
- Research Support, U.S. Gov't, P.H.S.
- Cells, Cultured
- Species Specificity
- Receptors, Peptide/metabolism/*physiology
- Receptors, Transferrin/metabolism
- tf -2fe
- rat hx
- non-specific binding
- hx receptors
- van dijk
- tfr expression