Effects of total parenteral nutrition on glutamine-glutamate relationships in neonatal piglets

We have previously demonstrated alterations in plasma glutamate [glu] as well as altered hepatic histology in neonatal piglets provided total parenteral nutrition (TPN] exposed to or protected from light (+/-) for 24h compared to sow-fed neonatal piglets. In this continuing investigation, we have determined plasma ammonia, glutamine synthetase [GS], glutaminase and glutamate dehydrogenase [GDH] in these animals. Four to 6 neonatal piglets were provided TPN [+L] or were agematched sow-fed piglets. After 7d of the respective treatments, blood and liver were obtained. Results [plasmal on day 7 [Mean ±SD, p <0.05 vs TPN + LI: Plasma TPN t L SOW-FED GLU.umol.dL^-1 12.914.3 7.9 ±0.7 GS, umol.h^-1 85.6 ±26.1 41.7 ±11.7 Glutaminase, g.L^-1 0.027 ±0.006 0.01610.006 GDH, U.L^-1 3.7 ±1.6 2.8 ±0.9 Plasma ALT but not AST was higher in sow-fed (p<0.05), gin and ammonia were not significantly different between the two groups, whereas hepatic gin was significantly greater in the sow-fed animals. Hepatic glu was about 45% lower in TPN vs sow-fed animals. Although gin and ammonia were similar in plasma, increased glutaminase and GS activity were observed; plasma urea was also similar in the two groups. These results provide further evidence for alterations in gln/glu homeostasis in short term TPN and bears investigation.