AJP - Regulatory, Integrative and Comparative Physiology, Vol 268, Issue 2 549-R561, Copyright © 1995 by American Physiological Society
Rates of local cerebral protein synthesis in the rat during normal postnatal development
Y. Sun, G. E. Deibler, J. Jehle, J. Macedonia, I. Dumont, T. Dang and C. B. Smith
Laboratory of Cerebral Metabolism, National Institutes of Mental Health, Bethesda, Maryland 20892.
The degree of recycling of leucine derived from protein breakdown into the
precursor pool for protein synthesis was measured in rat brain at different
postnatal ages, and age-specific values were used in the calculation of
regional (local) rates of cerebral leucine incorporation into protein
(lCPSleu) in 44 brain regions and the brain as a whole. Early in
development, a greater fraction of the precursor leucine pool is derived
from protein breakdown, indicating that protein degradation is higher in
young rats compared with adults. In whole brain and in most regions, values
for lCPSleu were highest at 10 days and gradually decreased with age. By 60
days of age, values in cortex were approximately 60% of those at 10 days of
age. In the paraventricular and supraoptic nuclei of the hypothalamus,
however, lCPSleu increased during development, reaching peak values in
adults. In white matter of the cerebellum and the cerebrum, peaks of
lCPSleu were reached at 14 and 21 days, respectively, approximately at the
times of maximum rates of myelination.
