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The pubertal‐related decline in cellular proliferation and neurogenesis in the dentate gyrus of male rats is independent of the pubertal rise in gonadal hormones
Author(s) -
Ho Amy,
Villacis Allison J.,
Svirsky Sarah E.,
Foilb Allison R.,
Romeo Russell D.
Publication year - 2012
Publication title -
developmental neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.716
H-Index - 129
eISSN - 1932-846X
pISSN - 1932-8451
DOI - 10.1002/dneu.20987
Subject(s) - neurogenesis , dentate gyrus , doublecortin , hippocampal formation , endocrinology , medicine , biology , hippocampus , bromodeoxyuridine , gonadal hormones , hormone , neuroscience , immunohistochemistry , castration
Pubertal development is marked by significant decreases in cellular proliferation and neurogenesis in the dentate gyrus of the hippocampal formation. Although it is unclear what mediates these developmental changes in the dentate gyrus, gonadal hormones have been implicated in modulating many neurobiological processes during puberty and various parameters of neurogenesis in adulthood. Thus, it is possible that the gradual and sustained increase in gonadal hormones experienced during puberty plays a role in these changes in neurogenesis. In this experiments, we first quantified cellular proliferation and neurogenesis using 5‐bromo‐2′‐deoxyuridine (BrdU) and doublecortin (DCX) immunohistochemistry, respectively, in the dentate gyrus of prepubertal (30 d), midpubertal (45 d), and adult (90 d) male rats. We found the decline in BrdU and DCX cell numbers throughout these ages was coincident with increases in their plasma testosterone levels. We next tested whether exposure to the pubertal rise in gonadal hormones was necessary for this decrease in hippocampal neurogenesis to occur. Thus, we examined cellular proliferation and neurogenesis in intact 30 day (prepubertal) and 60‐day‐old (late‐pubertal) rats, as well as 60‐day‐old rats that had previously been gonadectomized or sham‐gonadectomized at 30 days of age. Although we again found the expected decline in BrdU and DCX cell numbers between 30 and 60 days of age in the intact groups, there were no differences among the 60‐day‐old animals, regardless of gonadal status. These data indicate that the pubertal‐related decline in hippocampal cellular proliferation and neurogenesis is independent of the pubertal change in gonadal hormones. © 2011 Wiley Periodicals, Inc. Develop Neurobiol 72: 743–752, 2012