Effects of Morphine on Serum Reproductive Hormone Levels and the Expression of Genes Involved in Fertility-related Pathways in Male Rats

The effects of morphine on serum reproductive hormone levels and markers involved in fertility-related pathways were evaluated. A total of 30 male Wistar rats were divided into three groups (n = 10) and intraperitoneally administered the following substances for 20 days: two single daily doses of morphine (10 mg/kg; morphine group), saline (healthy saline), and intact group. After confirming the morphine dependence of the experimental groups, all the animals were sacrificed and their total testis tissue was extracted and stored at −80 °C until use. Male reproductive parameters (blood serum of testosterone, luteinizing hormone, and follicle-stimulating hormone) and using Q-PCR and western blot, we evaluated mRNA and protein expression of CREM, TBP, CREB1, HDAC1, and FOS involved in fertility-related pathways were analyzed and compared in the testis samples. The luteinizing hormone and testosterone levels were significantly lower in the morphine-administered group than in the saline and intact groups (P < 0.05). Moreover, the expressions of all five target genes were downregulated in the morphine group (P < 0.05). The protein expression of all five target proteins was downregulated in the morphine group (P < 0.05). We concluded that morphine could decrease the reproductive parameters in male rats.