Reproductive status influences the survival of new cells in the dentate gyrus of adult male meadow voles

Reproductive status influences cell proliferation and the survival of new cells in the dentate gyrus of adult laboratory-reared and wild female meadow voles; reproductively inactive (RI) females have more proliferating cells and more labeled cells that survive 5 weeks vs. 2 It than reproductively active (RA) females. However, the effect of season has only been studied in a wild sample of male meadow voles and factors such as age and experience that have been shown to influence neurogenesis in the dentate gyrus of adult mammals cannot be controlled in a wild sample. Therefore, we investigated whether reproductive status regulates neurogenesis (cell proliferation and/or the survival of new cells) in the dentate gyrus of laboratory-reared adult male meadow voles so that confounding variables could be controlled. Males were acclimated to a short- or a long-photoperiod to simulate the non-breeding or breeding season, respectively, and reproductive status was verified by testes mass. The density of labeled cells was similar in RI and RA males (P = 0.20) 2 h after an injection of bromodeoxyuridine (50 mg/kg) but the density-of labeled cells was elevated in the RA males relative to the RI males 5 weeks after an injection of [H-3]thymidine (5 muCi/g; P less than or equal to 0.04). The results suggest that reproductive status regulates the survival of new cells within the dentate gyrus of adult male meadow voles but not cell proliferation. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved.