AJP - Endocrinology and Metabolism, Vol 268, Issue 5 E925-E931, Copyright © 1995 by American Physiological Society

ARTICLES

Magnesium deficiency enhances basal glucose disposal in the rat

P. Lowney, T. S. Hannon and A. D. Baron
Department of Foods and Nutrition, Purdue University, West Lafayette 47907, USA.

To investigate the contribution of hepatic and peripheral tissues to the enhanced glucose disposal rate (Kg) observed in magnesium (Mg)-deficient rats, euglycemic-hyperinsulinemic clamps were performed with continuous infusion of [3-3H]glucose and three insulin infusion rates, 1, 8, and 16 microU.kg-1.min-1. Moderately Mg-deficient (Mg-, 4.2 microM Mg/g diet) and Mg-adequate (Mg+, 16.7 microM Mg/g diet) Sprague-Dawley rats were studied after 3 wk of dietary treatment. Growth, fasting glucose, and insulin concentrations were not affected by dietary treatment. Basal hepatic glucose output (HGO) and glucose disposal (Rd) were increased by 24% in Mg- rats (P < 0.001). After 1 microU insulin.kg-1.min-1 infusion, Rd and the glucose infusion rate that maintained euglycemia were significantly increased in Mg- rats by 24 and 46%, respectively. However, when the increase in Rd above baseline was examined, no significant differences were observed. Therefore, the increased basal glucose disposal observed in Mg- rats may be mediated by noninsulin-dependent mechanisms. Insulin suppression of HGO during 1 microU insulin.kg-1.min-1 infusion was greater in Mg- rats (43%) compared with Mg+ rats (27%, P < 0.05). In conclusion, the increased Kg observed in Mg- rats is likely to be caused by an increase in noninsulin-mediated glucose uptake and an enhancement of hepatic insulin sensitivity.

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				M. A. B. Reis, F. G. R. Reyes, M. J. A. Saad, and L. A. Velloso Magnesium Deficiency Modulates the Insulin Signaling Pathway in Liver but Not Muscle of Rats J. Nutr., January 1, 2000; 130(2): 133 - 138. [Abstract] [Full Text]