Inability to experimentally produce a polyneuropathy in dogs given chronic oral low level lead.

Electromyographic examinations were performed at various times over a 40 week period in four mature dogs receiving chronic oral low doses of lead acetate and a control dog receiving sodium acetate. Blood lead levels in the four dogs were elevated (mean values 1.15, 2.18, 1.13 and 1.72 mumol/liter). No clinical signs of lead intoxication were present. Two dogs had evidence of a nonregenerative anemia. Neither needle electromyographic nor nerve conduction velocity studies showed evidence of a polyneuropathy. Teased nerve fiber preparations of proximal and distal segments of the ulnar and tibial nerves and muscle biopsies of distal appendicular muscles were normal in all dogs. Light microscopic examination of the brain, kidneys and liver revealed no abnormalities in the two dogs necropsied. In conclusion, a polyneuropathy was not produced experimentally in dogs ingesting low doses of inorganic lead for up to 40 weeks.