
cell proliferation
in experimental hydronephrosis
and compensatory renal hyperplasia
mitosis counts and autoradiographic counts of nuclei labeled with
tritiated thymidine were made in the renal cortex of male rats in which
the left ureter was ligated.  these were compared with corresponding
counts in the remaining kidney after left nephrectomy, and in sham-
operated controls 24, 48 and 72 hours after operation.  the cortex of
the kidney on the obstructed side showed a greater number of tritium-
labeled nuclei and mitotic figures than in the kidney undergoing com-
pensatory hyperplasia.  epithelial and interstitial cells responded simul-
taneously on the obstructed side, whereas in the remaining kidney after
nephrectomy, the epithelial response preceded a slight interstitial re-
sponse by 48 hours.  the contralateral kidney in rats subjected to
ureteral ligation showed no response.
we concluded that the early response of increased dna synthesis
and cell division in the obstructed kidney was not mediated by humoral
factors; it was localized and probably had a different mechanism than
the proliferative response occurring in compensatory renal hyperplasia.
