Postprandial level of free amino acids in fish brain

1. Free amino acids were examined in common carp (Cyprinus carpio L.) brain 3, 6, 24 and 72 hr after a meal. 2. In common carp brain glutamic acid (409.6 +/- 37.6 mg/100 g dry matter), threonine (232.8 +/- 24.6) and histidine (191.3 +/- 70.1) were the most abundant free amino acids. 3. The ratios between the brain and the whole blood concentrations (B/W) expressed as the amounts of moles per tissue water were examined. 4. Glutamic acid, histidine, threonine, alanine, methionine, serine and glycine were found in consistently higher concentration in fish brain than in blood.