Fathers play an important role in the development of brain and species typical behavior like mother in monogamous mammals,but the exact nature of this process is not well understood.Especially,little research has addressed whether paternal care can alter levels of hippocampal glucocorticoid receptor (GR) and brain-derived neurotrophic factor (BDNF),and basal levels of serum corticosterone (CORT) and adrenocorticotropin (ACTH).Using socially monogamous mandarin voles (Microtus mandarinus),the present study showed that paternal deprivation significantly decreased GR and BDNF protein expression in the CA1 and CA2/3 of hippocampus.In the dental gyrus,the decrease of GR and BDNF expression was also evident in the females but not in males.Paternal deprivation significantly up-regulated levels of serum CORT and ACTH in females,but not in males.These findings demonstrate that paternal deprivation alters HPA axis activity in a sex-specific way; these changes in stress hormones may be associated with alteration in hippocampal BDNF and GR levels.