Seite - (000153) - in Biomedical Chemistry: Current Trends and Developments

individuals (Guerrero-Romero, 2013). Often, circulating and/or intracellular magnesium levels are reduced under insulin resistance/T2DM in (obese) children, adolescents and adults (Takaya, 2004; Huerta, 2005; Belin, 2007; Wells, 2008; Celik, 2011). Lecube et al. provided evidence that T2DM was the main factor accounting for the hypomagnesemia found in morbidly obese individuals. They observed that the percentage of morbidly obese individuals with serum magnesium concentration lower than 0.75 mmol L-1 was three fold higher in T2DM patients than in non-T2DM subjects. They also found that not only the degree of blood glucose control (when considering fasting plasma glucose and HbA1c levels) and serum magnesium concentration were significantly and negatively correlated but also fasting plasma glucose and HbA1c levels were, in multiple linear regression analysis, independently associated with serum magnesium concentration. Additionally, in the morbidly obese patient subgroup that went through bariatric surgery, serum magnesium levels increased in T2DM subjects in whom diabetes resolved; serum magnesium levels lasted unchanged in whom T2DM did not resolve (the same happened in non-T2DM obese subjects) (Lecube, 2012). The mechanisms by which T2DM could lead to low serum magnesium levels remain to be fully understood. However, insulin resistance, hyperinsulinemia, hyperglycemia and/or glycosuria may negatively interfere with renal reabsorption of magnesium, contributing to hypomagnesemia (McNair, 1982; Djurhuus, 1995; Barbagallo, 2007; Belin, 2007; Lecube, 2012; Takaya, 2012). Insulin has a prime role in magnesium metabolism regulation and insulin resistance/inhibition of insulin-stimulated glucose uptake may decrease magnesium uptake by tissues and increase magnesium efflux from tissues (Takaya, 2004; Barbagallo, 2007; Belin, 2007). Magnesium is a cofactor of several enzymes involved in insulin and glucose metabolism, among other processes (Takaya, 2004; Barbagallo, 2007; Belin, 2007; Guerrera, 2009; Takaya, 2012). Briefly, insulin binds to its receptor (IR) inducing its autophosphorylation on tyrosine residues and, subsequently, tyrosine residues phosphorylation of its substrates (IRS) and Src homology 2 domain containing transforming protein 1 (Shc). Phosphorylated IRS, particularly IRS1 and 2, activate