title: Magnesium deficiency improves glucose homeostasis in the rat: studies in vivo and in isolated islets in vitro.
abstract: The serum mineral levels, glucose disappearance rate (kg), total area under the glucose (DeltaG) and insulin (DeltaI) 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 DeltaG and DeltaI. 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, DeltaG and DeltaI compared with the CO-11 and SCO groups. However, a significantly lower kg and higher DeltaG and DeltaI 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.
authors.affiliation: Departamento de Fisiologia e Biofisica, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, Brazil.
authors.forename: M A
authors.initials: MA
authors.lastname: Reis
authors.forename: M Q
authors.initials: MQ
authors.lastname: Latorraca
authors.forename: E M
authors.initials: EM
authors.lastname: Carneiro
authors.forename: A C
authors.initials: AC
authors.lastname: Boschero
authors.forename: M J
authors.initials: MJ
authors.lastname: Saad
authors.forename: L A
authors.initials: LA
authors.lastname: Velloso
authors.forename: F G
authors.initials: FG
authors.lastname: Reyes
mesh_terms: D000818:Animals; D019540:Area Under Curve; D005947:Glucose / Q000378:metabolism* / Q000494:pharmacology; D006706:Homeostasis; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism*; D008274:Magnesium / Q000008:administration & dosage; D008275:Magnesium Deficiency / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012636:Secretory Rate / Q000187:drug effects
chemical_list: D007328:Insulin; D008274:Magnesium; D005947:Glucose