effect of heroin used in iran on fertility in mice (balb/c)

background: heroin as opium is being used in two pure and impure forms with known disastrous effects on different body organs including genital system. the aim of this study was to determine the changes in testosterone secretion, the percentage of fertility, changes of the body and testis weight, and gonado somatic index in mice (ballb/c). materials and methods: a total of 90 adult male and female mice were selected and male mice were assigned into three control and two experimental groups. different experimental groups of heroin-dependant mice (50 mg/kg ip for 3 days, twice daily), were divided into two groups. one of which received heroin 5 mg/kg ip and the other 5 mg/ml ip twice daily for a period of 40 days. then the serum of 24 male mice was studied. after copulation of the male and female mice, the rate of infertility was estimated and the proportion of body and testis weight and gonado somatic index in tested groups was determined. results: serum testosterone showed insignificant difference between the control groups, however, its level did differ significantly between the control and experimental groups (p<0.05). meanwhile, fertility rate did not differ between the control groups, but showed a significant difference between the control and the experimental groups (p<0.05). body and testis weight differed significantly between the control and the experimental groups (p<0.05). conclusion: heroin may reduce the testosterone level and testis weight, while it is associated with infertility.