Effect of chronic ethanol administration on brain protein breakdown in mice in vivo.

Brain proteins of BALB/cBy mice were labeled for a period of 8 days by a single intraperitoneal injection of valine. Following this the mice received 10% ethanol and protein breakdown was estimated from the release of label from brain proteins. Ethanol intake resulted in a significant inhibition of cerebral protein breakdown in vivo as measured in whole brain and in subcellular brain fractions (myelin, synaptosomes, mitochondria, microsomes, and nuclei). The intake of 10% ethanol for 4.5 months resulted in minor alterations in amino acid levels; increase in some and decrease in others were observed in plasma and brain, but most of the changes were not significant (P greater than 0.05). The uptake of AIB in brain was decreased 17% by prolonged ethanol intake.