Longevity and aging of mice from lines divergently selected for body weight for 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 body weight during their life span. The differences regarded maturation rate, the length of the life time, reproduction performance, and fertility. Females from the light line (L) were fertile for a longer period of time than those from the heavy line (C), while the process of spermatogenesis disappearance started earlier in the light males than in the heavy ones. There were also differences in the relative weight of adrenal glands and histopathological changes connected with the hyperplasia of their spindle cells. The adrenal glands in females from both lines were heavier than in males. A significantly higher percentage of the cortex cell hyperplasia was observed in adrenals of mice from the C line than the L line. The differences were also scored between mice from the selection lines in relation to the length of their life. On average, the L mice lived 30 days longer than the heavy ones. Body weight loss was observed earlier in the old heavy males than the L ones and this was correlated with the earlier mortality in this group of animals.