Effects of undernutrition during suckling on phosphoryl serine levels in nuclear and synaptosomal proteins from cerebral cortex of rats.

The effect of undernutrition during suckling on phosphoryl serine levels was investigated in rats. Young rats were undernourished by suckling their lactating mothers fed an 8% (by weight) protein diet. Mothers of normal rats were fed a 25% protein diet. After weaning (21 d), normal and undernourished rats were fed a 25% protein diet until 90-120 d of age. Previously we observed that undernutrition during suckling decreases the levels of phosphoryl serine in nuclear proteins from the whole brain of adult rats. In this paper we report more specifically on the effect of undernutrition during this period on the levels of phosphoryl serine in nuclear and synaptosomal proteins from the cerebral cortex of young and nutritionally rehabilitated adult rats. In young, undernourished rats the levels of phosphoryl serine in nuclear proteins were significantly lower (28%) than those in control animals. This alteration persisted in nutritionally rehabilitated adult rats. Serine and protein levels in cerebral cortex were the same in all groups. No alteration in the levels of phosphoryl serine in the synaptosomal fraction was observed.