Related Experiment Videos
A plasma factor inhibiting erythrocyte magnesium efflux
J G Henrotte1, G Franck, M Santarromana
1CNRS, Faculté de Pharmacie, Paris, France.
Abstract:
When incubated at 37 degrees C for 5 h in a magnesium- and calcium-free phosphate buffer solution (PBS), rat and mouse erythrocytes lose 30-40% of their Mg content. However, no Mg loss is observed if these erythrocytes are incubated in their own plasma. In order to investigate this phenomenon, murine erythrocytes were incubated in PBS, in human and murine blood plasmas, and fetal calf serum diluted in PBS (1/4), and in PBS supplemented with MgCl2, CaCl2, and crystallized plasma proteins at concentrations equal to those obtained in plasma/PBS solutions. Erythrocyte Mg efflux was significantly inhibited (P = 10(-8] by diluted human and rat plasmas but the time course of this inhibition was different with these two kinds of plasmas (P = 10(-4]. Mouse plasma and fetal calf serum also entailed a significant inhibition of Mg efflux, while the addition of Mg, Ca, and purified plasma proteins in the incubation medium had little effect. Blood plasma thus contains a factor inhibiting Mg efflux from murine erythrocytes and this effect is not explained by its content of magnesium, calcium, and proteins.
Insights
Erythrocytes lose magnesium in a special buffer, but not in blood plasma. Blood plasma contains a factor that inhibits this magnesium loss, independent of its magnesium, calcium, or protein content.
Area of Science:
- Biochemistry
- Cell Biology
- Physiology
Background:
- Erythrocytes (red blood cells) can lose significant magnesium (Mg) when incubated in magnesium- and calcium-free phosphate-buffered saline (PBS).
- This Mg efflux is notably absent when erythrocytes are incubated in their native plasma.
Purpose of the Study:
- To investigate the factor in blood plasma responsible for inhibiting erythrocyte magnesium efflux.
- To determine if plasma's Mg, Ca, or protein content explains the inhibition of Mg efflux.
Main Methods:
- Murine erythrocytes were incubated in various solutions: PBS, diluted human and rat plasmas, diluted fetal calf serum, and PBS with added MgCl2, CaCl2, and plasma proteins.
- Erythrocyte Mg efflux was quantified and statistically analyzed.
Main Results:
- Diluted human and rat plasmas significantly inhibited erythrocyte Mg efflux (P = 10⁻⁸).
- Mouse plasma and fetal calf serum also demonstrated significant inhibition of Mg efflux.
- The addition of magnesium, calcium, or purified plasma proteins to the incubation medium had minimal effect on Mg efflux.
Conclusions:
- Blood plasma contains a factor that actively inhibits Mg efflux from murine erythrocytes.
- This inhibitory effect is not attributable to the plasma's concentration of magnesium, calcium, or proteins.