TREATMENT WITH L-DEPRENYL PROLONGS LIFE IN ELDERLY DOGS

Eighty two beagle dogs ranging in age from 2.8 to 16.4 years and in we ight from 6.3 to 15.8 kg were allotted to 41 pairs and administered pl acebo or 1 mg/kg L-deprenyl orally once daily for 2 years and 10 weeks . When survivorship for all dogs in the study was analyzed there was n o significant difference between the L-deprenyl and placebo treated gr oups, most likely due to the (expected) survival of virtually all youn g dogs in both groups for the duration of the study. To assess whether L-deprenyl treatment begun in later life might enhance canine longevi ty in a fashion similar to that documented in rodents we also examined survival in a subset of elderly dogs who were between the ages of 10 and 15 yrs at the start of tablet administration and who received tabl ets for at least 6 months. In this subset, dogs in the L-deprenyl grou p survived longer (p < 0.05) than dogs in the placebo group. Twelve of 15 (80%) dogs in the L-deprenyl group survived to the conclusion of t he study, in contrast to only 7 of 18 (39%) of the dogs who received p lacebo (P = 0.017). Furthermore, by the time the first L-deprenyl trea ted dog died on day 427, 5 placebo treated dogs had already succumbed, the first on day 295. Specifically with respect to dogs, the findings reported herein suggest daily oral administration of 1 mg/kg L-depren yl prolongs life when begun in relatively healthy dogs 10-15 years of age and maintained for the duration of the individual's life, but in a ny event for no less than six months.