Electrogenic absorption of sugars and amino acids in the small intestine of the human fetus.
Some characteristics and the degree of intestinal absorption in the developing human fetus were examined by measuring solute evoked potentials and 14C-D-glucose uptake into the everted jejunal segments. In all segments, the Michaelis-Menten relationship was observed between D-glucose concentrations and the evoked potentials or D-glucose uptake. Increase of Na-ion concentrations enhanced both D-glucose evoked potentials and uptake. Both D-glucose and L-alpha-alanine evoked potentials increased in a significant correlation to the fetal age; however, the apparent Michaelis constants did not show any signficant change. The structural specificity of sugar for generating evoked potentials was the same as that reported for adult mammals. Among amino acids, only the L-form of neutral and acidic amino acids generated markedly high evoked potentials, but the basic ones hardly at all. Oligopeptides such as glycyl-glycine and glycyl-glycyl-glycine also generated high evoked potentials. Our results have indicated that the active transport system of sugars and amino acids in the human fetus have already developed by as early as the sixth month of gestation.
D000375:Aging; D000596:Amino Acids / Q000378:metabolism*; D001693:Biological Transport, Active; D050260:Carbohydrate Metabolism; D005071:Evoked Potentials; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007408:Intestinal Absorption; D007421:Intestine, Small / Q000196:embryology / Q000502:physiology*; D007583:Jejunum / Q000502:physiology; D008431:Maternal-Fetal Exchange; D011247:Pregnancy
D000596:Amino Acids