Glucose-fatty acid interactions in prepubertal and pubertal children: effects of lipid infusion

This investigation examined whether puberty differs from prepuberty in regard to the effects of increased free fatty acid (FFA) on in vivo glucose metabolism. Nine prepubertal and 13 pubertal healthy children were studied. Each subject was studied twice, once with 0.9% sodium chloride solution (control study) and once with 20% Intralipid infusion in the basal state and during a 3-h hyperinsulinemic-euglycemic clamp, with [6,6-2H2]glucose tracer. During control studies, prepubertal children had lower basal fat oxidation and higher insulin-mediated glucose disposal than pubertal adolescents. During Intralipid infusion, basal glucose uptake increased in prepubertal children but did not change in pubertal adolescents. Insulin-stimulated whole body glucose disposal did not change in prepubertal children (control 77.6 +/- 8.9, Intralipid 84.5 +/- 13.3 micromol x kg(-1) x min(-1)) but decreased in pubertal adolescents (control 55.0 +/- 3.6, Intralipid 46.7 +/- 3.4 micromol x kg(-1) x min(-1), P = 0.01) despite comparable decrements in glucose oxidaion. We conclude that in prepubertal children lipids exert effects in the basal state by stimulating hepatic glucose production and glucose disposal, whereas in pubertal adolescents they induce peripheral tissue insulin resistance by decreasing insulin-stimulated glucose uptake. This differential response could be due to developmental-maturational changes in tissue sensitivity and/or specificity to the glucose-FFA interaction.