Abnormal neuronal growth in the little (lit) cerebrum

Mice genetically deficient in growth hormone were compared with normal littermates for evidence of altered neuronal development. In the lit/lit motor cortex, area 6 of Caviness, cell number, stratification of neurons, and the proportionate layer widths were identical to those of the controls (lit/+). Examined by the Golgi-Cox method modified by Ramon-Moliner, however, the pyramidal neuron was found to have short primary dendrites with sparse branchings. This result was confirmed in sections stained for neuron-specific enolase. Therefore, we conclude that growth hormone has an independent action on neuronal development.