남성화 암쥐의 모리스 수중 미로 수행력 : 성에 따른 공간기억력과 테스토르테론 효과의 차이 = The Morris Water Maze Performance in Androgenized Female Rats : Sexual Dimorphisms in Spatial Memory and Effects of Testosterone

다국어 초록 (Multilingual Abstract)

Objectives : It is widely accepted that gonadal steroids are involved in organization and activation of sexual dimorphism in the brain areas related with spatial leaming. This study aimed to test the following hypothesis : 1) spatial memory is affected by sex, 2) this difference is related with brain differentiation by exposure to testosterone in the neonatal period, and/or 3) the sexual difference of spatial memory is the result of the interaction between organization of sexual dimorphism in the brain and the circulating testosterone after growing up.
Methods : Testosterone enanthate 100 ㎍, ('androgenized') orvehicle ('control') was randomly administered to 28 female and 25 male rat pups within 24 hour of birth. The escape latencies (EL) in Morris water maze were measured in 15 and 16 week of age with vehicle ('baseline') and with 10 μmol/kg of testosterone ('with testosterone'), respectively. Each session Consis-ted of 10 trials, and means of the last 5 trials were analyzed.
Results : The baseline EL of the males were significantly shorter than females regardless ofneonatal exposure to testosterone. With testosterone, EL of the androgenized females were significantly shorter than control females and comparable to those of males.
Conclusion : Neonatal exposure to testosterone in female rats may develop a tesosterone-dependent male-like spatial leaming system.