Cell proliferation in rat kidney induced by lead acetate and effects of uninephrectomy on the proliferation.

Effects of a single dose of lead (0.04 mg lead g body weight) on the proliferation of proximal tubular epithelium in rat kidneys were investigated by autoradiography over a period of 72 hours, using (3)H-thymidine as a label. The results demonstrate that cell proliferation was greatly stimulated within 2 days after lead was injected. The increase in DNA synthesis began about 20 hours after intraperitoneal injection of lead, reached a sharp peak at 30 hours, and declined rapidly thereafter. At the peak, the mean labeling activity was 40 times that observed in control rats. Cumulatively, an average of 14.5% of the proximal tubular epithelial cells were labeled 72 hours after lead was injected. When uninephrectomy was followed immediately by injection of lead, the stimulation of DNA synthesis in the remaining kidney was, on the average, greater than the sum of the separate effects of the two treatments. This indicates that the stimulatory effects of uninephrectomy and injection of lead on renal cell proliferation were additive.