ROTIFERS IN AGING RESEARCH - USE OF ROTIFERS TO TEST VARIOUS THEORIESOF AGING

Four theories of aging are discussed to examine how effectively they m ight explain the aging process in rotifers. One of the early theories, the rate of living theory of aging can perhaps be discounted. Althoug h the theory predicts that increased biological energy expenditure, in the form of increased activity or reproduction, would lead to a short er lifespan, these predictions are not born out by experimental eviden ce. At the whole animal level, a case can be made for a theory of prog rammed aging, where the end of reproduction signals the end of the lif espan. Support for this view comes from the observation that lifespan is positively correlated with reproductive parameters, that treatments that extend lifespan usually act to extend the reproductive period, a nd that the end of reproduction is associated with high mortality and senescent biochemical changes. Two molecular theories of aging are als o discussed; the free radical theory of aging and the calcium theory o f aging. These theories point to the fact that molecular damage accumu lates and that calcium influx increases in the course of aging. When f ree radical buildup or calcium homeostasis is reduced, lifespan is ext ended. A molecular explanation of aging does not necessarily exclude t he idea of programmed aging. It is probable that an eventual understan ding of the aging process will rest on both a physiological and molecu lar basis.