[Testing the effects of so-called geriatric agents]

The high average life expectation in the civilized and industrial countries can be attributed to a considerable extent to the achievements of the medical sciences. However, medical research also has the task of providing the physiological basis which will ensure that the extra years do not mean just an extension of the period of senility but instead form a period valuable for the individual and society. In accordance with the common definitions, one expects a "geriatric agent" (geriatricum) to slow down the aging process or to diminish its effects. Such influences are usually referred to as revitalization. However, a rejuvenation in the sense of a genuine reversal of the aging process is--according to our present knowledge--not possible. An objective assessment of revitalising effects can be reached by means of multivariate models of biological age, orientated on the aging process of a "normal population". However, research on human beings causes methodical difficulties and considerable expense because of the necessity for long-term studies and the importance of assessing psycho-social factors. Thus, it is necessary to test the effectiveness of "geriatric agents" primarily in the animal experiment. The laboratory rat seems well-suited for such studies. Using a multivariate model of the biological age of the rat, research into experimental influences on the aging process is demonstrated. The statistical testing and the analysis of the effects are carried out by means of discrimination analysis and factor analysis. With regard to the "geriatric agents" at present in use and the aims of experimental gerontology, it is established that such research has not yet been carried out to a satisfactory extent.