title: Rates of local cerebral protein synthesis in fetal and neonatal sheep.
abstract: During gestation there is likely to be a constantly changing rate of protein synthesis in the brain that may exhibit regional specificity. With the use of the quantitative autoradiographic L-[1-(14)C]leucine method for the determination of local rates of leucine incorporation into cerebral protein (lCPS(Leu)), we have sought to characterize this important process. lCPS(Leu) was measured in nine fetal sheep (118-139 days gestational age) and five newborn lambs (1-5 days of age). In other experiments, the fraction of leucine in the precursor pool for protein synthesis in the brain derived from the arterial plasma was determined to be 0.57 +/- 0.04 (mean +/- SE) in one fetus and two lambs. This value was used in the calculation of lCPS(Leu) in 35 regions of the central nervous system, pineal body, and whole brain. Regardless of age, lCPS(Leu) was highest in the pineal body, brain stem, and hypothalamic nuclei and lowest in white matter. In sensorimotor cortex, corona radiata, pyramidal tracts, and whole brain, lCPS(Leu) was positively correlated with prenatal age (P < or = 0.05). These increases in lCPS(Leu) probably reflect myelination in the cerebrum, which is known to occur in late gestation.
authors.affiliation: Department of Obstetrics and Gynecology, University of Florida Medical Center, Gainesville 32610, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Abrams
authors.forename: D J
authors.initials: DJ
authors.lastname: Burchfield
authors.forename: Y
authors.initials: Y
authors.lastname: Sun
authors.forename: C B
authors.initials: CB
authors.lastname: Smith
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001345:Autoradiography; D001921:Brain / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D002250:Carbon Radioisotopes; D004569:Electroencephalography; D005314:Embryonic and Fetal Development; D005333:Fetus; D005865:Gestational Age; D007930:Leucine / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*; D009928:Organ Specificity; D012044:Regression Analysis; D012756:Sheep
chemical_list: D002250:Carbon Radioisotopes; D009419:Nerve Tissue Proteins; D007930:Leucine