Effect of Acute and Chronic Acidosis on Glutamine Uptake in Kidney Slices of Newborn Rats

Abstract

Developmental changes in glutamine uptake, CO, and NH3 production was studied in kidney slices isolated from 12-, 18-, and 65-day-old rats under normal and acidotic conditions. The kidney slices from 12-and 18-day-old animals showed lower uptake of glutamine, CO, and NH3 production compared to 65-day-old animals. Chronic acidosis increased the ability of kidneys from postnatal rats to accumulate and metabolize glutamine but this increment was lower than the adults. Acute acidosis of newborn animals failed to show any significant changes in glutamine uptake and metabolism even though the degree of acidosis reached was the same between chronic and acute acidotic groups. Newborns failed to show an optimal pH for glutamine uptake and metabolism under normal and acidotic conditions. Along with other factors, the inability of newborn kidneys to increase transport of glutamine during an acid challenge can also explain the lowered ammonia production of newborn rats. 149

New insights into the pathogenesis of renal tubular acidosis - from functional to molecular studies

“…Premature infants, however, do present an inability to acidify the urine as a consequence of insufficient ammoniagenesis [62,63]. Glutamine uptake, NH 3 production, and excretion into the tubular fluid are lower in neonatal rats after an acid load [64].…”