Abstract
This study on ACTH-treated suckling mice was undertaken to elucidate the effect of ACTH on neuron-al growth and behavioral development. One unit of ACTH was administered successively from the day seven to eleven. ACTH-treated mice showed extreme impairment of both body weight and brain weight growth. These impairments were improved before 40 days of age. Dendritic arbolization of and V layer neurons and myelination of pyramidal tracts were also impaired. The difference of dendritic growth between ACTH-treated mice and normal controls became little at 60 days of age. The difference of myelin lamellae between these two groups was significant at 20 days of age. There was no significant difference at 30 days of age. ACTH treatment also delayed the behavioral and motor development. In our experiments, the effects of ACTH were reversible, which were inhibitory to the neuronal development
