Physical exercise-induced hypoglycemia caused by failed silencing of monocarboxylate transporter 1 in pancreatic beta cells.

Exercise-induced hyperinsulinism (EIHI) is a dominantly inherited hypoglycemic disorder characterized by inappropriate insulin secretion during anaerobic exercise or on pyruvate load. We aimed to identify the molecular basis of this novel disorder of beta -cell regulation. EIHI mapped to chromosome 1 (LOD score 3.

The plasma membrane lactate transporter MCT4, but not MCT1, is up-regulated by hypoxia through a HIF-1alpha-dependent mechanism.

The monocarboxylate transporter MCT4 mediates lactic acid efflux from most tissues that are dependent on glycolysis for their ATP production. Here we demonstrate that expression of MCT4 mRNA and protein was increased >3-fold by a 48-h exposure to 1% O(2), whereas MCT1 expression was not increased. The effect was mimicked by CoCl(2) (50 microm), suggesting transcriptional regulation by hypoxia-inducible factor 1alpha (HIF-1alpha).

Factors associated with iron depletion and iron deficiency anemia among Arabic preschool children of the United Arab Emirates.

Objective: The purpose of this study was: 1. To estimate the prevalence of iron depletion and iron deficiency anemia in preschool Arabic children of the United Arab Emirates (UAE), and 2. To determine the risk factors associated with these conditions in this population of children.