RÉSUMÉ
The aim of this study was to assess the possible mechanisms for the toxic impact of marijuana smoke on the level of male reproductive hormones and their related genes expression. Male albino rats were enrolled in this study and divided into: (I) control group; (II) and (III) Marijuana smoke exposed groups in which the animals were exposed to marijuana smoke daily for two and four weeks respectively. Serum free testosterone, FSH and LH were assayed. Brain follicle stimulating hormone gene (FSH-B) and luteinizing hormone gene (LH-B) as well as testicular cytochrome P19 (CYP19) genes expression were evaluated. Histological examination of brain and testis tissues was done. Marijuana smoke produced significant reduction in serum reproductive hormones levels. Similarly, it caused significant down-regulation in the expression of reproductive hormones related genes. Histological investigation of brain tissue of marijuana smoke exposed rats revealed marked deterioration in medulla oblogata and cerebellum. While, histological examination of their testis tissues showed no histopathological changes.The present findings suggest that marijuana smoke adversely affects male reproductive function due to its ability to suppress gonadotropin output from pituitary in addition to its impact on the structure and/or function of DNA nucleotide sequences of reproductive hormones related genes. Marijuana smoke could impair fertility in male rats through alteration in circulating levels of reproductive hormones and down-regulation of the expression level of reproductive hormones related genes.