Insulin-like immunoreactivity in the rat brain during postnatal ontogenesis

The regional distribution and the cellular localization of insulin-immunoreactive material in the rat brain has been studied during postnatal ontogenesis by use of radioimmunoassay and immunocytochemistry. It could be shown that there is a decrease in the amount of the peptide in the rat brain during postnatal maturation of the organ. This decline in insulin concentration is morphologically evident by a strong reduction of insulin positive nerve cells. Our findings support the hypothesis that insulin might play important roles as a nerve growth-promoting factor.