Age-related changes in paternal responses of gerbils parallel changes in their testosterone concentrations

Results of previous studies In our laboratory have shown that testosterone (T) inhibits parental response in adult male Mongolian gerbils. Here, we ex amined developmental changes in parental responses of male gerbils before,, hiring, and after a naturally occurring surge in T that peaks on Day 75 pos tpartum. On the hypothesis that T inhibits parental response in male gerbil s, we predicted that (a) 75-day-old male gerbils would be less responsive t o neonates than would either younger or older male gerbils, and (b)young ma le gerbils whose T titers were rising as the litters that they were helping to rear matured would show a decrease over days in parental effort relativ e to older male gerbils whose T titers were falling as the litters that the y were helping to rear matured. Both predictions were confirmed, providing evidence consistent with the view that naturally occurring, developmental c hanges in circulating concentrations of T play a role in age-related change s in the level of parental response of male Mongolian gerbils. (C) 2001 Joh n Wiley & Sons, Inc.