Summary:
Eighty two beagle dogs ranging in age from 2.8 to 16.4 years and in
weight from 6.3 to 15.8 kg were allotted to 41 pairs and administered
placebo 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 no
significant difference between the l-deprenyl and placebo treated groups,
most likely due to the (expected) survival of virtually all young dogs in
both groups for the duration of the study. To assess whether l-deprenyl
treatment begun in later life might enhance canine longevity in a fashion
similar to that documented in rodents we also examined survival 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 recieved tablets for at least 6
months. In this subset, dogs in the l-deprenyl group 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 the study, in contrast to
only 7 of 18 (39%) of the dogs who recieved placebo (p=0.017). Furthermore,
by the time the first l-deprenyl treated 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-deprenyl 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 any event for no less than six months.