[32P]Phosphate incorporation into nucleotides of the dorsal root ganglia (DRG) was studied after a crush lesion of the rat sciatic nerve. DRG were labelled during a 2-h, in vitro incubation in a balanced salt solution containing [32P]orthophosphate, 1, 2, 4 and 8 days after the crush lesion. Nucleotides were analyzed by HPLC on an ion-exchange column. An increased incorporation of 32P was found in DRG of the injured nerve for all the studied time periods. This increase was unevenly distributed among the nucleotides. UTP, CTP and ADP showed the largest and most persistent increases in labelling. The specific activity of 4 analyzed nucleotides (ATP, ADP, UTP and CDP) remained constant in DRG from crushed nerves. Thus, the observed increase in 32P-labelling could not solely be due to an increased uptake of label but must also reflect an enhanced metabolism of nucleotides in regenerating DRG. The finding that alterations of nucleotide metabolism could be observed within one day after the crush lesion suggests that this response can be used as a valuable tool for studies of the initial events of regeneration.