Magnesium deficiency improves glucose homeostasis in the rat: studies in vivo and in isolated islets in vitro

• Published in: British journal of nutrition 2001-05, Vol.85 (5), p.549-552
• Main Authors: Reis, Marise A. B., Latorraca, Márcia Q., Carneiro, Everardo M., Boschero, Antonio C., Saad, Mário J. A., Velloso, Lício A., Reyes, Felix G. R.
• Format: Article
• Language: English
• Subjects: Animals; Area Under Curve; Biological and medical sciences; Diet; Experiments; Glucose; Glucose - metabolism; Glucose - pharmacology; Glucose homeostasis; Homeostasis; Insulin; Insulin - blood; Insulin - metabolism; Insulin Secretion; Insulin sensitivity; Islets of Langerhans - drug effects; Islets of Langerhans - metabolism; Magnesium; Magnesium - administration & dosage; Magnesium deficiency; Magnesium Deficiency - metabolism; Male; Medical sciences; Metabolic diseases; Metabolism; Nutrition research; Other nutritional diseases (malnutrition, nutritional and vitamin deficiencies...); Rats; Rats, Wistar; Secretory Rate - drug effects
• ISSN: 0007-1145; 1475-2662
• DOI: 10.1079/BJN2000294

The serum mineral levels, glucose disappearance rate (kg), total area under the glucose (ΔG) and insulin (ΔI) curves, and static insulin secretion were compared among rats fed a Mg-deficient diet for 6 (DF-6) or 11 (DF-11) weeks, and rats fed a control diet for the same periods (CO-6 and CO-11 groups). No change in glucose homeostasis was observed among DF-6, CO-6 and CO-11 rats. DF-11 rats showed an elevated kg and a reduced ΔG and ΔI. For evaluating the effect of supplementation, rats fed a control or Mg-deficient diet for 6 weeks were then fed a Mg- supplemented diet for 5 weeks (SCO and SDF groups respectively). The serum Mg levels in SDF rats were similar to those in CO-11 and SCO rats, but higher than in the DF-11 group. SDF rats showed similar kg, ΔG and ΔI compared with the CO-11 and SCO groups. However, a significantly lower kg and higher ΔG and ΔI were observed in SDF compared with DF-11 rats. Basal and 8.3 mmol glucose/l-stimulated insulin secretion by islets from DF-11 rats were higher than by islets from CO-11 rats. These results indicate that moderate Mg depletion for a long period may increase the secretion and sensitivity to insulin, while Mg supplementation in formerly Mg-deficient rats may prevent the increase in sensitivity and secretion of insulin.