Differences in protein synthesized in vivo and in vitro by cells associated with the cerebral microvasculature. A protein synthesized in response to trauma?

A protein of molecular weight 71,000 (P₇₁) was synthesized by cells associated with the cerebral microvasculature in telencephalon slices incubated in vitro. This protein, however, was not synthesized in vivo. There was a 30 min delay in the synthesis of P₇₁ by brain slices. During this lag period a new ribonucleic acid species which was required for P₇₁ synthesis was produced in the slices. After this delay P₇₁ became a major product of protein synthesis. P₇₁ was also produced by microvasculature enriched fractions isolated from telencephalon.This protein may be involved in the initial response of the vascular system to injury.