Genetic regulation of blood and tissue magnesium content in mammals.

Investigations on the genetic regulation of blood and tissue magnesium content are reviewed. Red blood cell and plasma Mg concentrations are genetically controlled as shown by twin and family studies in men and by inbred strain comparisons in mice. The coefficients of heritability are high and significant. Mice liver, spleen and kidney Mg concentrations yield similar results. These Mg-controlling genetic factors involve at least three components: genes associated with the major histocompatibility complex (HLA and H-2 tissue antigens), other genes, and tissue factors modulating the respective importance of the first two factors. Preliminary investigations also suggest that these genetic factors may play a role in immune processes and stress reactions. The selective breeding of two new strains of mice for high and low blood Mg values presently in progress is expected to throw new light on this genetic system.