Lead poisoning: rapid formation of intranuclear inclusions.

A single dose of lead (0.05 milligram per gram of body weight) induced characteristic intranuclear inclusions in the epithelium of proximal tubules in rat kidney within 1 to 6 days. The development of the intranuclear inclusions is thus an acute manifestation of lead poisoning, not a delayed one, as has been thought hitherto. Cytoplasmic structures resembling the intranuclear inclusions and situated in the vicinity of endoplasmic reticulum were regularly found in cells bearing the pathognomonic intranuclear inclusions. The latter and the cytoplasmic structures may be derived from a common precursor, perhaps a soluble protein-lead complex.