Maternal food restriction, brain polysomes and poly-U stimulated protein synthesis in the newborn and 21-day-old rat progeny

Abstract

Effect of maternal dietary restriction during the period of gestation (EI) and during the period of growth, gestation and lactation (EII) on (i) the polysomal profiles (ii) distribution of 14C-phenylalanine and 3H-orotate into membrane bound and free polysomes and ribosomes and (iii) ribosomal response to the addition of poly-U in the incorporation of 14C-phenylalanine was investigated in the brain of the neonatal (N) and 21-day-old (T) progeny. Polysomal profile showed variable degrees of reductions in the membrane bound ribosomes, free polysomes and monoribosomes in the brain of N and T progeny of EI and EII groups compared with WF group. Distribution of radioactive phenylalanine and orotate also showed variable responses in the membrane bound ribosomes free polysomes and the monoribosomes of the brain of N and T progeny of EI and EII groups. EII N progeny generally had a lower distribution and EII group T progeny had a higher distribution than EI group in each component of the polysomal profile. Ribosomes from the brain of N and T progeny of EI and EII groups responded less actively to the addition of poly-U than WF group. Synthesis of protein/synthesis of polyphenylalanine ratio (which roughly represents polysomes/monosomes ratio) demonstrated variable responses in the brain of N and T progeny of EI and EII groups compared with WF group. In T progeny when WF polysomes were incubated with EI or EII group pH-5 enzymes, the incorporation increased significantly and was higher in EII group than EI group. Incubation of EI polysomes with EII pH-5 enzyme demonstrated a significant increase in the incorporation. These results clearly demonstrate that maternal food restriction during various physiological periods had a profound effect on brain polysomes and consequently the protein synthesizing machinery in the N and T progeny.