Effect of altered neonatal nutrition on the development of enzymes of lipid and carbohydrate metabolism in the rat.

Rats were overnourished during suckling by litter-size manipulation in order to investigate the possible association of overfeeding in infancy with the development of obesity in later life. Rats were raised in litters of 4, 10 and 16 corresponding to overfeeding, normal feeding and underfeeding during the suckling period. From 6-19 days post partum, growth rates of pups from different litter sizes were significantly different (4 greater than 10 greater than 16). Differences in mean body weights between the groups continued to increase after weaning when all groups were allowed access to diet ad libitum and the significant weight difference between overfed and normally fed rats persisted into adult life in both males and females. Overfed animals showed modifications in the development of activities of a number of hepatic enzymes involved in lipid and carbohydrate metabolism. In later life (20 weeks) neonatally overnourished rats exhibited alterations in hepatic enzyme activities that reflected an increased capacity for lipid synthesis by the liver. "Supernourishment" of neonatal rats (by intubation with glucose of animals in small litters), accelerated the appearance of some of these alterations. These studies show that the pattern of early infant nutrition can profoundly influence the activities of liver enzymes in later, adult life.