Effects of gestational hypoxia on mRNA levels of Glut3 and Glut4 transporters, hypoxia inducible factor-1 and thyroid hormone receptors in developing rat brain.

Alterations of brain development result from noxious intrauterine signals, as oxygen deprivation, which decrease glucose energetic yield. To verify the hypothesis that a defect of brain energetic adaptation is responsible for these alterations, we have studied the effects of gestational hypoxia (10% oxygen during the last 2 weeks of fetal life) on cerebral ontogenesis of glucose transporters which control the limiting step of glucose utilization by neurons. This study is realised in rats by quantification of whole brain Glut3 and Glut4 mRNA in 14- and 19-day-old embryos (E14, E19), newborn (P0) and 7 postnatal-day-old rats (P7) by using reverse transcription-polymerase chain reaction (RT-PCR) method.

Biochemical and functional evidences for a GLUT-4 homologous protein in avian skeletal muscle.

The characteristics and modulation of glucose transport were investigated in skeletal muscles of 5-wk-old Muscovy ducklings (Cairina moschata). Glucose uptake by sarcolemmal vesicles isolated from gastrocnemius muscle followed typical Michaelis-Menten kinetics with a K(m) value (17 mM) similar to that described in equivalent mammalian preparations. Western blot analysis of duckling sarcolemma using antibodies directed against rat GLUT-4 transporter revealed an immunoreactive protein of similar molecular mass (45 kDa) to that present in rats.

Effect of chronic cold exposure on Na-dependent D-glucose transport along small intestine in ducklings.

In conditions of chronic cold exposure, ducklings develop a nonshivering thermogenesis that requires a high energy expenditure. Therefore, energy supply becomes essential to cold-acclimated ducklings, which increase their intake of carbohydrate-rich food. The aim of this work was to investigate the effect of cold acclimation on the activity of the intestinal brush-border Na(+)-D-glucose cotransport, which is the first major step controlling glucose entrance into an organism.

Dietary regulation of fructose metabolism in the intestine and in the liver of the rat. Duration of the effects of a high fructose diet after the return to the standard diet.

In this research on metabolic effects of a high fructose diet, we studied the duration of these effects by measuring the specific activity of 8 enzymes stimulated by such a diet, on days, 0, 3, 6, 9, 15, after the return to a normal diet. In the intestinal mucosa, ketohexokinase, aldolase, triokinase, fructose-diphosphatase, and glucose-6-phosphatase specific activities were still entirely or partially stimulated on the 15th day after return to the standard diet. The stimulation of glucose-6-phosphatase and pyruvate kinase specific activities stopped quickly.

Fructose transport by rat intestinal brush border membrane vesicles. Effect of high fructose diet followed by return to standard diet.

1. D-Fructose uptake in isolated rat intestinal brush border membrane comprised a simple diffusional component and a saturable, carrier-mediated, component. The latter did not follow typical Michaelis-Menten kinetics and appeared as a low affinity, high capacity process (Kt = 110 mM, Jmax = 160.