Exchangeable magnesium pool masses in spontaneously hypertensive rats.
We explored magnesium (Mg) metabolism by determination of exchangeable Mg pool masses and Mg kinetic parameters using stable Mg isotopes in spontaneously hypertensive rats (SHRs). Classical intracellular and extracellular Mg status biomarkers were also measured. Male SHRs and their male Wistar Kyoto (WKY) controls were fed a semipurified diet containing Mg 550 mg /kg for 2 weeks. Each rat received then an intravenous injection of 1.37 mg (25)Mg. The plasma (25)Mg disappearance curve over the next 7 days was used to measure the mass and fractional transport rate of 3 rapidly exchanging Mg metabolic pools, M1, M2, and M3. In the SHRs, plasma and erythrocyte Mg levels and urinary Mg excretion were not modified compared with their control WKYs, but tibia Mg level was significantly lower in the SHRs. Pool M3, the deep tissue pool, was significantly lower in SHRs compared with WKYs, but pools M1 and M2, the extracellular Mg pools, were statistically similar. The fractional transport rate of Mg from M1 to M2 and from M2 to M1 in the SHRs was higher than in the controls. The half-life of M1 was significantly decreased in SHRs compared with WKYs. In conclusion, this work demonstrates a decrease in intracellular Mg stores in SHRs compared with WKYs and disturbance of Mg exchanges in extracellular Mg, confirming a Mg metabolism disturbance in spontaneously hypertensive rats. Further work is now needed to elucidate the origin of the Mg depletion in SHRs and to explore Mg pools in hypertensive patients.
Feillet-Coudray
Christine
C
Centre de Recherche en Nutrition Humaine d'Auvergne, Unité Maladies Métaboliques et Micronutriments, INRA, Centre de Recherche Clermont-Ferrand/Theix, Saint Genès Champanelle, France.
Gueux
Elyett
E
Lab
Claudine
C
Rayssiguier
Yves
Y
Coudray
Charles
C
D000818:Animals; D015415:Biomarkers; D001835:Body Weight / Q000502:physiology; D004032:Diet; D006207:Half-Life; D006973:Hypertension / Q000235:genetics / Q000378:metabolism*; D007202:Indicators and Reagents; D008274:Magnesium / Q000097:blood / Q000378:metabolism* / Q000493:pharmacokinetics; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
D015415:Biomarkers; D007202:Indicators and Reagents; D008274:Magnesium