Cerebral blood flow and metabolism in fasting neonatal piglets

Cerebral blood flow and cerebral metabolism were studied in 8 fasting neonatal piglets. Cerebral blood flow was not significantly different (p greater than 0.1) at 24 h (75.0 +/- 30.7 ml/min/100 g) and 48 h (74.2 +/- 32.3 ml/min/100 g) of age. Blood glucose concentration was lower in 48-hour-old fasted piglets (1.27 +/- 0.60 mmol/l) in comparison with 24-hour-old fasted animals (2.90 +/- 0.52 mmol/l), and cerebral glucose utilisation rate was also reduced in the 48-hour-old piglets (17.6 +/- 6.0 mumol/min/100 g at 48 h, 34.2 +/- 12.2 mumol/min/100 g at 24 h). Blood lactate concentration and cerebral lactate utilisation rate were not significantly different at 24 and 48 h of age. Brain lactate utilisation accounted for approximately 10% of cerebral oxygen utilisation at 48 h in fasted piglets. Cerebral glucose and lactate utilisation at 48 h accounted for approximately 66% of cerebral oxygen uptake, indicating that other substrates make a major contribution to cerebral metabolic requirements in fasting neonatal piglets.