Poly(adenosine diphosphoribose) polymerase activity and adenosine diphosphate ribosylation of proteins during pancreatic degeneration and regeneration.

The activity of poly(adenosine diphosphoribose) polymerase was measured in isolated rat pancreatic nuclei and was found to increase during pancreatic nuclei which follows an ethionine treatment, although a possible relationship of enzyme activity to the initial degenerative phase may also be considered. There is a 2-fold increase in the enzyme activity during the destruction process which remains high during the regeneration period. This increase of activity observed during regeneration is not related to a decrease of the polymer degradation. We have studied the adenosine diphosphate ribosylation of proteins during pancreatic regeneration, and we have found increases in the level of adenosine diphosphate ribosylations of these proteins just before regeneration and during the regeneration period. The in vivo adenosine diphosphate ribosylation of nuclear proteins does not correlate with synthetase activity measured in nuclei during the degeneration period but does correlate during the regeneration period and thereafter with the relative amount of enzymatic activity found in nuclei. Furthermore, as verified by autoradiography, labeling of the nuclei by polyadenosine diphosphoribose polymer shows a marked increase during regeneration.