Immunochemical measurement of myelin basic protein in developing rat brain: an index of myelin synthesis.

The initial time and rate of myelin basic protein synthesis in neural tissues of the rat have been measured from birth to 120 days. The protein was quantitated by a radioimmunoassay directly applied to unfractionated cerebrum, cerebellum, olfactory bulb, midbrain, brain stem, optic and trigeminal nerve, and areas of the spinal cord. Because the protein is a specific myelin constituent and its appearance correlates precisely with the synthesis of myelin lipids, the data in this report can be interpreted in terms of myelin synthesis and oligodendrocyte activity. The results show striking heterogeneity in the initial time and rate of myelin synthesis in neural tissue.