UNEXPECTED ASSOCIATION BETWEEN REPRODUCTIVE LONGEVITY AND BLOOD MAGNESIUM LEVELS IN A NEW MODEL OF SELECTED MOUSE STRAINS

Two recently described mouse strains, with high (MGH) and low (MGL) bl ood magnesium (Mg) levels were obtained by selection over 19 generatio ns. Both strains exhibit strong differences for characteristics genera lly known to be related to blood Mg levels, such as increased stress s ensitivity and stress-induced aggressivity in MGL mice. In contrast, w hile experimental Mg deficiency due to low oral Mg intake has been sho wn to shorten life span and lower reproductive ability, reproductive l ongevity was longer in the MGL than in the MGH strain. Interestingly, the life spans of the two strains are very similar. Although this char acter could have been fixed in the strains by chance, with no relation ship to the blood Mg level, the possibility of a causal link with the selection cannot be ruled out and is discussed. Regardless of the mech anisms at stake, the MGH and MGL strains appear to constitute a new mo del for the study of the relationships between reproductive longevity and blood Mg levels.