title: Testosterone ameliorates streptozotocin-induced memory impairment in male rats.
abstract: OBJECTIVE
  To study the effects of testosterone on streptozotocin (STZ)-induced memory impairment in male rats.
  
  
  METHODS
  Adult male Wistar rats were intracerebroventricularly (icv) infused with STZ (750 μg) on d 1 and d 3, and a passive avoidance task was assessed 2 weeks after the first injection of STZ. Castration surgery was performed in another group of rats, and the passive avoidance task was assessed 4 weeks after the operation. Testosterone (1 mg·kg(-1)·d(-1), sc), the androgen receptor antagonist flutamide (10 mg·kg(-1)·d(-1), ip), the estrogen receptor antagonist tamoxifen (1 mg·kg(-1)·d(-1), ip) or the aromatase inhibitor letrozole (4 mg·kg(-1)·d(-1), ip) were administered for 6 d after the first injection of STZ.
  
  
  RESULTS
  STZ administration and castration markedly decreased both STL1 (the short memory) and STL2 (the long memory) in passive avoidance tests. Testosterone replacement almost restored the STL1 and STL2 in castrated rats, and significantly prolonged the STL1 and STL2 in STZ-treated rats. Administration of flutamide, letrozole or tamoxifen significantly impaired the memory in intact rats, and significantly attenuated the testosterone replacement in improving STZ- and castration-induced memory impairment.
  
  
  CONCLUSIONS
  Testosterone administration ameliorates STZ- and castration-induced memory impairment in male Wistar rats.
authors.affiliation: Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz 51664, Iran.
authors.forename: Alireza Mohajjel
authors.initials: AM
authors.lastname: Nayebi
authors.affiliation: Department of Biology, Science and Research Branch, Islamic Azad University, Fars, Iran.
authors.forename: Seyedreza
authors.initials: S
authors.lastname: Pourrabi
authors.affiliation: Department of Biology, Science and Research Branch, Islamic Azad University, Fars, Iran.
authors.forename: Seyedebrahim
authors.initials: S
authors.lastname: Hossini
mesh_terms: D000728:Androgens / Q000627:therapeutic use*; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D002369:Castration / Q000009:adverse effects; D008297:Male; D008568:Memory / Q000187:drug effects; D008569:Memory Disorders / Q000139:chemically induced* / Q000188:drug therapy* / Q000209:etiology; D017208:Rats, Wistar; D013311:Streptozocin; D013739:Testosterone / Q000627:therapeutic use*
chemical_list: D000728:Androgens; D013739:Testosterone; D013311:Streptozocin