Subject(s)
Electromyography , Adolescent , Child , Child, Preschool , Female , Humans , Infant , Male , Movement Disorders/diagnosis , Muscular Diseases/diagnosis , Neuromuscular Diseases/diagnosisABSTRACT
In view of the importance of free fatty acids (FFA) as substrates for the mature kidney, fatty acid oxidation by developing rat kidney has been investigated in vitro. Incubations of kidney slices from fetal stages (days 20 and 21 of gestation) and from days 1, 5, 10, 20, and 30 after birth have been carried out in Krebs-phosphate, pH 7.4, containing 0.5 or 1.5 mM U-14C-palmitate. Palmitate uptake and oxidation into CO2 were measured after 90 min incubation. At 0.5 mM concentration of palmitate in the incubation medium, fetal kidney exhibited a low uptake and a very low oxidation of palmitate into CO2. These two parameters increased only after birth and were maximum with slices from suckling rats between days 5 and 10 after birth. Palmitate oxidation increased only with postnatal days slices (maximum during the suckling period) and not with fetal slices. An increase in palmitate oxidation could be obtained with slices from kidneys of fetuses whose mothers had been starved 48h. These data suggest that the development of renal capacity for FFA oxidation during the perinatal period could be related to nutritional supply.
Subject(s)
Fatty Acids, Nonesterified/metabolism , Kidney/embryology , Animals , Energy Intake , Female , Food Deprivation , Gestational Age , Kidney/metabolism , Palmitates/metabolism , Pregnancy , RatsABSTRACT
Slices of fetal rat kidney were incubated for 90 min at 37 degrees C in Krebs phosphate buffer containing [14C]glucose. Glucose uptake did not change significantly with age, but the 14CO2 evolved from [14C]-glucose dropped, and the lactate concentration at the end of incubation rose. The increasing development of the medulla during gestation was believed to be responsible for this. Higher glucose uptake and lower [14C]glucose incorporation into CO2 was observed in whole fetal slices compared to cortical slices from adult kidney, incubated following the same procedure. These results might be due to the smaller number of functionally differentiated nephrons present in fetal compared to adult kidney. Competition between glucose and lactate, normally found at high concentrations in fetal blood, and between glucose and beta-hydroxybutyrate, known to increase in circumstances such as starvation in the mother, showed a decrease in the 14CO2 evolved from [14C]glucose. This suggests that both these substrates might be oxidized by fetal kidney. This was confirmed by experiments in which lactate or beta-hydroxybutyrate replaced glucose in the incubation medium. Further, both these substrates seemed to be preferential fuels for oxidation compared to glucose, and their possible role in saving glucose is discussed.
