Decreased synthesis of ciliary neurotrophic factor in degenerating peripheral nerves.

The mRNA for ciliary neurotrophic factor in normal and injured sciatic nerves has been assayed by an RNase protection assay. The endoneurial concentration of ciliary neurotrophic factor mRNA is diminished in the distal nerve stump within three days of sciatic nerve transection, is less than one tenth of normal after one week, and remains low if regeneration does not occur. The synthesis of ciliary neurotrophic factor in injured peripheral nerves is decreased when and where the synthesis of nerve growth factor is increased.