Postponing Senescence

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Science  13 Feb 2009:
Vol. 323, Issue 5916, pp. 854
DOI: 10.1126/science.323.5916.854b

Although aging affects us all, concerns about reproductive aging generally refer to females. But females have not cornered this market: Reproductive aging in men is evidenced by decreased fertility that correlates with decreased testosterone and sperm motility. Likewise, rodent studies reveal compromised reproduction with advancing age, and rodent male reproductive success has been shown, in some studies, to be affected by environmental factors such as the presence of females or social isolation.

Schmidt et al. have documented a fertility effect on male mice aging either in isolation or in cohabitation with females. Naïve females were bred with 16- to 32-month old males in cohorts spaced 2 months apart. A significant effect was seen: Males separated from females were less fertile by 26 months, and this correlated with the onset of abnormal spermatogenesis. On the other hand, fertility was not affected in males up to 32 months if they had been housed with females. Hence, reproductive aging is delayed when females are present, and this delay represents a 20% extension of the normal period of fertility. Nevertheless, when fertility begins to decrease, it does so at the same rate regardless of social environment. These data on male reproductive aging may influence the management of livestock and endangered species as well as provoking discussion about human fertility. — BAP

Biol. Reprod. 80, 10.1095/biolreprod.108.073619 (2009).

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