Vulnerability of developing brain. III. Development of four enzymes in the brains of normal and undernourished rats

Abstract

The developmental profiles of 4 enzymes representative of different metabolic pathways or subcellular organelles have been determined in the homogenates of whole brains of control and undernourished male rats aged 0–21 days. Undernutrition was achieved by underfeeding the dams during gestation and lactation such that the young (at 21 days) had a deficit in body weight of 66% compared with control animals. The activities (per g wet wt of tissue) of the enzymes examined rose 3- to 5-fold between birth and 21 days in control animals. The development of succinate dehydrogenase (acceptor ferricyanide), fructose diphosphate aldolase and acetylcholinesterase was retarded by undernutrition. The activity deficits at 21 days were respectively 21%, 14% and 11% compared with a deficit in brain weight of 27%. The developmental profile of β- N-acetylglucosaminidase which is probably a lysosomal enzyme, was unaffected by undernutrition. These results are considered to indicate that the control of enzyme maturation in the brain may have both chronological and developmental components. Enzyme maturation in the brain appears to be restricted by undernutrition, though not as much as might be suggested by the reduction in brain weight.