title: Distribution of nutrients between fetal brain body during rat development.
abstract: During prenatal development, the distribution of nutrients between brain and body is influenced by many factors. Fetal and neonatal ratios may serve as indices of the final outcome; brain weight/body weight (Rw), brain DNA/body DNA (RDNA) and brain protein/body protein (Rprot; similar to Rw). These ratios decrease with fetal age but this dependence on age disappears towards term. Within one age, these ratios show considerable variability (up to 14%), from litter to litter, and within litters. The variability is not due to variation in water contents ( less than 1%). An extensive study of 2,089 normal newborns revealed that 7.5% had Rw values significantly higher than the mean for the population. Of these, 35% had normal body weights but significantly higher brain weights. Thus, they do not represent previously studied cases of general (brain and body) overdevelopment; rather, they represent cases of favorable brain versus body growth, i.e. distribution of nutrients between brain and body that is more favorable for the brain. Such a favorable distribution may be caused by maternal factors if it affects entire litters (3% of all affected) or by fetal factors, if it affects only individuals within a litter (49%).
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism; D001834:Body Water / Q000378:metabolism; D001835:Body Weight; D001921:Brain / Q000196:embryology* / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D005333:Fetus / Q000378:metabolism*; D005865:Gestational Age; D009747:Nutritional Physiological Phenomena; D009929:Organ Size; D051381:Rats
chemical_list: D004247:DNA