Longevity and aging of mice from linesdivergently selected for body weightfor over 90 generations

We have analysed the differences between longevity and aging process in two lines of mice selected divergently for body weight. As a result of long-term selection,the mice from two lines varied significantly in bodyweight during their life span. The differencesregarded maturation rate, the length of the life time,reproduction performance, and fertility. Females fromthe light line (L) were fertile for a longer period oftime than those from the heavy line (C), while theprocess of spermatogenesis disappearance startedearlier in the light males than in the heavy ones. Therewere also differences in the relative weight ofadrenal glands and histopathological changes connectedwith the hyperplasia of their spindle cells. Theadrenal glands in females from both lines were heavierthan in males. A significantly higher percentage of thecortex cell hyperplasia was observed in adrenals ofmice from the C line than the L line. Thedifferences were also scored between mice from theselection lines in relation to the length of theirlife. On average, the L mice lived 30 days longerthan the heavy ones. Body weight loss was observedearlier in the old heavy males than the L ones andthis was correlated with the earlier mortality in thisgroup of animals.