Lanthanon-induced hepatotoxicity and its prevention by pretreatment with the same lanthanon.

Intravenous injection of the light lanthanon praseodymium nitrate (10 mg/kg) into rats causes a marked liver toxicity which becomes manifest in hypoglycemia, inhibition of RNA and protein synthesis and accumulation of fat in liver tissue. All these effects can be nearly abolished by pretreating rats with a small dose (5 mg/kg) of the same lanthanon. This is neither due to a decreased uptake into the liver nor to an increased excretion rate of the lanthanon. It is assumed that the pretreatment may increase unspecific binding sites or reversibly block them, thus protecting the organism from the irreversible lethal effect.