Intracellular magnesium and adipokines in umbilical cord plasma and infant birth size.

Many epidemiologic studies have disclosed that restricted fetal growth has been associated with an increased risk of insulin resistance in adulthood. We studied the relationship of intracellular magnesium [Mg2+]i in cord blood platelets to adipocytokine and birth size. The subjects were 20 infants with small for gestational age (SGA) and 45 infants with appropriate for gestational age (AGA). By using a fluorescent probe, we examined [Mg2+]i of platelets in the cord blood. Cord plasma insulin, IGF-I, ghrelin, adiponectin, plasminogen activator inhibitor-1 (PAI-1), and leptin levels were determined with the use of ELISA. Mean [Mg2+]i was lower in the SGA than in the AGA groups (p < 0.001). Adiponectin and IGF-I were also lower in the SGA than in the AGA, whereas PAI-1 was higher in the SGA. [Mg2+]i was significantly correlated with birth weight, birth length, and adiponectin. Birth weight was also correlated with cord plasma IGF-I, adiponectin, and leptin. Quantitative insulin sensitivity check index (QUICKI) was lower in the SGA group than in the AGA group. [Mg]i and adiponectin were correlated with QUICKI in all subjects. [Mg]i, as well as leptin and IGF-I, reflect the extent of fetal growth. Decreased [Mg2+]i may be involved in the underlying processes to insulin resistance.