DNA (Cell Number) and Protein in Neonatal Rat Brain: Alteration by Timing of Maternal Dietary Protein Restriction

Abstract
Pregnant rats were fed a protein-free diet during five periods of pregnancy: days 0 to 10, 10 to 15, 13 to 18, 15 to 20 or 10 to 20, and normal diet during the remaining time. In the case of the days 0 to 10 group, 62% of the females failed to litter. There was no significant change in the amount of food intake of pregnant animals in any of the groups; yet in all cases there were significant decreases in body weights, cerebral weights, cerebral DNA (cell number) and cerebral protein of the neonatal animals even though, until day 15, the total protein increment of the embryo and its supporting tissue constitutes only an insignificant fraction of the average maternal protein intake. An explanation of the neonatal underdevelopment, involving the triggering of a hormonal mechanism and resulting in a placental deficiency has been proposed. After day 15, this mechanism may be supplemented by an actual deficiency of the amino acids required for fetal protein synthesis.