The dentate gyrus is sexually dimorphic in prepubescent rats: testosterone plays a significant role

In a morphological examination of the hippocampal formation of pre-pubescent rats, a testosterone-related sexual dimorphism was observed. The dentate gyrus granule cell layer was greater (8-9%) in width and length and laterally asymmetrical in males and in testosterone-treated females. This dimorphism was previously observed in adult rats. These data demonstrate that the dimorphism exists prior to puberty and is therefore not dependent on hormone changes associated with this event. In addition, a correlation between the size of this cell layer and performance on a spatial task were observed.