Erythrocyte magnesium influx and efflux in solid tumor bearing mice.
Mg metabolism is modified in tumors and tumor-bearing organisms. In particular cancer patients often display elevated erythrocyte Mg levels. For a better understanding of the increased erythrocyte Mg content, we attempted to determine Mg fluxes in erythrocytes from tumor-bearing mice by Mg stable isotopes, using a method developed in our laboratory. To characterize the animal Mg status, blood and tissue Mg levels and hematological parameters were assayed. Results showed that in tumor-bearing mice total erythrocyte Mg was about 46% higher than in controls, whereas plasma and tissues Mg levels were not modified; red blood cells and hemoglobin as well as hematocrits were significantly decreased, while mean corpuscular volume and mean corpuscular hemoglobin were slightly but significantly increased in tumor-bearing mice compared to controls (by 3% and 4%, respectively), a picture corresponding to a normochromic, slightly macrocytic anemia. Erythrocyte Mg efflux was about 20% higher (404 + 59 versus 330 + 45 micromol/L, respectively, p < 0.05) in tumor-bearing mice compared to controls, whereas influx was not significantly modified (130 + 11 versus 122 + 19 micromol/L, respectively). Our data therefore exclude that the increased Mg content observed in erythrocytes of tumor-bearing mice is due to decrease of Mg efflux, or to an increase of Mg influx. On the other hand, the increased Mg content observed in erythrocytes of tumor-bearing mice could simply result from an increase of young Mg-enriched erythrocytes produced by the enhanced erythropoiesis which follows tumor-induced anemia.
Feillet-Coudray
C
C
CRNH d'Auvergne, Unité Maladies Métaboliques et Micronutriments, INRA, Clermont-Ferrand, France. feillet@clermont.inra.fr
Nasulewicz
A
A
Jaffrelo
L
L
Thien
S
S
Coudray
C
C
Rambeau
M
M
Gueux
E
E
Rayssiguier
Y
Y
Opolski
A
A
Wolf
F I
FI
Mazur
A
A
D000818:Animals; D018827:Carcinoma, Lewis Lung / Q000097:blood*; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D008175:Lung Neoplasms / Q000097:blood*; D008274:Magnesium / Q000097:blood*; D051379:Mice; D008810:Mice, Inbred C57BL; D009929:Organ Size
D008274:Magnesium