X-Message-Number: 10605 Date: Sun, 18 Oct 1998 10:32:50 -0400 From: Thomas Donaldson <> Subject: CryoNet #10597 To Mr. Brian Delaney: You are wrong in your statement that only deprenyl has shown an increase in maximal lifespan. I will say, though, that a lot depends on just how you define it. Furthermore, calorie restriction, unlike the various drugs, has been known for more than 60 years and has been repeated with variations many more times than any extant drug study. It's also true that ANTIOXIDANTS have at best shown an increase in average lifespans. But antioxidants are far from the only ones that have been tried. IF we define maximal lifespan as the maximum lifespan of any animal in the drug versus the control group, then L-Dopa,melatonin,dilantin, and CoQ10 all show curves with the maximum lifespan reached by the treated animals. This work was also done after the possibility of calorie restriction in treated animals was known and controlled for. HGH (human growth hormone) also provides an interesting special case, since the experimenters seem to have run out of their supply (it was more expensive than now, and remains expensive) before their test mice died off. By that time, ALL their controls had died off, while slightly under half the test mice still remained alive. You may wish to argue against a small number of experiments. Fine. You may also have some disagreement with the definition above of "maximal lifespan". The only cure for the first problem is more experiments. As for defining "maximal lifespan", especially when the number of experiments on a drug or treatment is small, I find it difficult to work out any clear definition other than the one I gave. NO one keeps statistics on the lifespan of every lab mouse in existence, and such statistics are unlikely to mean very much anyway. As for the maximal lifespan of any lab mouse involved in an experiment with drug X, there are problems, too. The conditions in each experiment are unlikely to be identical, either in the strain of mouse or in their treatment and the treatment of controls. I will be blunt, not about what you say but about the current state of aging research: I think that the emphasis on calorie restriction, with little attempt to work out exactly why and how it has its effects, simply won't get us very far. The issue is that of finding some regimen which works better because it touches on fundamental causes of aging better. Yes, the experiments on all the drugs I listed should be replicated. They might even tell us why calorie restriction works, if pursued. I do find it odd that an experiment in which treated animals live longer than untreated ones, and even have a maximal lifespan longer than that for untreated ones, will not at least be replicated and studied for what it might tell us about aging. Best and long long life, (by whatever means!) Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=10605