title: Expression of cAMP-responsive element modulator (CREM) in rat testes following chronic cocaine administration.
abstract: OBJECTIVE
  c-AMP-responsive element modulator (CREM), one of the nuclear factors involved in the regulation of gene expression by cAMP, has an important role in spermatogenesis. Our recent study has shown that chronic administration of cocaine to male rats results in disruption of spermatogenesis, including reduction of germ cells. As a further step toward understanding this process, we have studied the role of CREM in cocaine-induced testicular damage.
  
  
  METHODS
  Sprague-Dawley rats were administered cocaine hydrochloride subcutaneously daily for 90 days. Control animals received equal volumes of normal saline daily for 90 days. Testes were removed after 15, 30, 90 days of cocaine administration. Total RNA was extracted from the testes and subjected to RT-PCR. Testicular tissue was also homogenized in a lysis buffer, and Western blotting was performed using anti-CREM antibody.
  
  
  RESULTS
  RT-PCR analysis detected a single fragment of approximately 520 base pairs (bp) in control testes at all time points. The cocaine-treated testes showed reduced expression of CREM fragment. Western blot analysis using CREM antibodies confirmed the RNA data. There were reduced CREM proteins in the cocaine-treated testes compared with controls.
  
  
  CONCLUSIONS
  The CREM gene is essential for spermatogenesis. Our results indicate that the reduction in testicular CREM expression may be one of the mechanisms responsible for disruption or impairment of spermatogenesis in the testes following chronic cocaine administration.
authors.affiliation: Department of Urology, Wayne State University, School of Medicine, Detroit, Michigan, USA. hli@med.wayne.edu
authors.forename: Haikun
authors.initials: H
authors.lastname: Li
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Dunbar
authors.forename: C B
authors.initials: CB
authors.lastname: Dhabuwala
mesh_terms: D000818:Animals; D003042:Cocaine / Q000633:toxicity*; D000242:Cyclic AMP; D051786:Cyclic AMP Response Element Modulator; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D018765:Dopamine Uptake Inhibitors / Q000633:toxicity*; D005786:Gene Expression Regulation; D007279:Injections, Subcutaneous; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012097:Repressor Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013091:Spermatogenesis / Q000187:drug effects*; D013737:Testis / Q000187:drug effects / Q000502:physiology
chemical_list: D004268:DNA-Binding Proteins; D018765:Dopamine Uptake Inhibitors; D012097:Repressor Proteins; D051786:Cyclic AMP Response Element Modulator; D000242:Cyclic AMP; D003042:Cocaine