title: Toxicity of Chevron Escravos crude oil and chemical dispersant on guinea pig testicular function.
abstract: BACKGROUND
  Chemical contaminants have been found to affect reproductive functions in mammals. This study investigated the effect of Chevron Escravos crude oil and Emulsol L.W. dispersant on the testicular functions of guinea pig.
  
  
  METHODS
  Eight groups of seven sexually mature male guinea pigs each were given 1250, 2500, or 5000 mg/kg of crude oil and dispersant for 7 days. The fluid and food intake and body weight of the animals were measured daily throughout the study. After the exposure period, sperm quality analysis was carried out, and fructose and lactate dehydrogenase were analyzed in tissue homogenate, while testosterone and estradiol were assayed in blood. The right testis was also processed for histological analysis.
  
  
  RESULTS
  The epididymal sperm number and fructose level of treated animals showed a significant dose-dependent decrease (p<0.05) compared with controls. Also, sperm motility and morphology were altered in the treated groups, while testosterone and estradiol levels were increased significantly (p<0.05) in the treated groups. Histological examination showed signs of toxicity in the treated animals.
  
  
  CONCLUSIONS
  From the findings, it was evident that Chevron Escravos crude oil and Emulsol L.W. oil dispersant are able to cause acute testicular toxicity in guinea pigs. The possible mechanism of toxicity is suggested to be by stimulation of hormone production from the adrenal cortex, causing a negative feedback on gonadotropin-releasing hormone in the pituitary gland to suppress spermatogenesis.
authors.forename: Onyenmechi Johnson
authors.initials: OJ
authors.lastname: Afonne
authors.forename: Igwebuike Victor
authors.initials: IV
authors.lastname: Onyiaorah
authors.forename: Orish Ebere
authors.initials: OE
authors.lastname: Orisakwe
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000737:chemistry / Q000633:toxicity*; D004958:Estradiol / Q000097:blood; D006168:Guinea Pigs; D007928:Lethal Dose 50; D008297:Male; D010578:Petroleum / Q000633:toxicity*; D013081:Sperm Motility / Q000187:drug effects; D013091:Spermatogenesis / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D013501:Surface-Active Agents / Q000737:chemistry / Q000633:toxicity*; D013737:Testis / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D013739:Testosterone / Q000097:blood; D023382:Toxicity Tests, Acute
chemical_list: D004785:Environmental Pollutants; D010578:Petroleum; D013501:Surface-Active Agents; D013739:Testosterone; D004958:Estradiol