[Cyclic feeding regime--a new model for experimental gerontology].

The influence of specific cyclic feeding regime (CFR) providing 30% loss of body weight for 14 days and 14 days recovery period followed by the standard feeding diet in the course of 30 days, on rat life span was investigated. It has been shown that young and old animals differed in intensity loss and recovery of body weight after three cycles CFR. The mass of liver changes cyclically as well as body weight. It was found that the content of glucose and protein in serum was cyclically changed only in the first cycle of CFR; during the second cycle of the same feeding regime a completely different trend of these parameters was observed. Such nature of the dynamics on the same type of repetitive exposure indicates change in adaptation strategies. This indicates the usage of alternative metabolic pathways that provide survival in extreme conditions. Each subsequent cycle of weight loss-restoration differed from the previous one and had a pronounced age-related character. Animals that have successfully passed three consecutive CFR beginning from 19-months of age had longer life span as compared with the control animals group. CFR can be used as a new model in gerontology providing increased life when transferred on a diet not only young but also old animals.

[Metabolic memory enhances hormesis effect to the copper ions in age-depended manner].

The ability of young and old rats to manifest the hormesis effect to lethal doses of copper sulphate and the ability to save the induced "adaptive" pattern of redistribution of copper ions after the transfer of animals in the standard conditions is the mechanism of metabolic memory. It was found that pretreatment of animals with low-dose (1 mg per 100 g body mass, i.e. 33% of the lethal dose) of copper sulfate induced the formation of their resistance to lethal doses (3 mg per 100 g), so the hormesis effect was manifested. Hormesis effect depended on the number of pre injections of small doses of copper sulphate in an S-shaped manner. The protective effect increased after 1 to 3 of preliminary injections of copper sulfate, and after four or more injections the hormesis effect decreased. It is shown that the cardinal role in intracellular pattern of copper ion redistribution play heat-stable copper binding proteins 12 kDa cytosolic proteins. The formed "adaptive" pattern of intracellular distribution of the copper ions may be reproduced, after at least, one month. The prolonged hormesis effect can be attributed to the forming metabolic memory. The intracellular distribution pattern of the copper ions was age-dependent. Age-related differences were found in hormesis effect induced by copper ions, which results in increased binding capacity of copper binding proteins in old animals, with a higher content of copper ions in the mitochondria and microsomes as compared to young animals.