Preclinical toxicology studies with the new dopamine agonist pergolide. Acute, subchronic, and chronic evaluations

Pergolide (LY127809, CAS 66104-23-2), a dopamine agonist for the treatment of Parkinson's disease, was evaluated for toxicity in acute, subchronic, and chronic studies. Acute toxicity tests using oral, intravenous and intraperitoneal routes were conducted in rats, mice, rabbits, and dogs. The acute oral median lethal doses (MLD) ranged from 8.4 to 33.6 mg/kg in Wistar and Fischer 344 rats, and from 54.0 to 87.2 mg/kg in ICR mice. Oral doses of 20 and 25 mg/kg produced no mortality in rabbits or dogs, respectively. The MLD by the iv route ranged from 0.59 to 0.87 mg/kg for Fischer 344 rats and from 11.6 to 37.1 mg/kg for ICR mice. The predominant signs of toxicity in the acute studies included hyperactivity, poor grooming, ptosis, aggressive behavior, increased gnawing activity, tremors, convulsions, and emesis. In the subchronic and chronic studies, Fischer 344 rats, B6C3F1 mice, and beagle dogs were administered pergolide either by gavage or in the diet for up to 1 year. Daily doses in these studies ranged up to 20 mg/kg for rats, 45 mg/kg for mice, and 5 mg/kg for dogs. The predominant treatment-related effects seen in these studies were attributable to the pharmacologic activity of pergolide. These consisted primarily of CNS-mediated clinical signs in rats and dogs, weight loss or decreased weight gain, emesis in dogs, and inhibition of lysis of corpora lutea with a corresponding increase in the weight of the uterus and ovaries. Pergolide treatment was not associated with any specific target organ toxicity.(ABSTRACT TRUNCATED AT 250 WORDS)