Effect of lead on the activity of antioxidant enzymes and male reproductive hormones

Environmental exposure to heavy metals such as lead is detrimental to male reproductive system. Lead induced oxidative stress is believed to contribute immensely to male infertility. The study was designed to investigate the influence of environmental lead exposure on the activities of antioxidant enzymes and male reproductive hormones levels in male individuals of Bagega and Kawaye villages of Anka Local Government Area of Zamfara State Nigeria. Sixty male individuals (40 lead exposed and 20 controls) were recruited. Activities of antioxidant enzymes (serum superoxide dismutase [SOD], catalase [CAT] and glutathione peroxidase [GPx]) and malondialdehyde [MDA] levels were determined using standard methods. Blood lead levels and reproductive hormones levels were measured with atomic absorption spectrophotometer and ELISA method, respectively. The lead exposed subjects had mean blood lead levels (BLLs) 208.72 ± 19.89 µg/dl and were within the reproductive age group (15-45 years). The activities of all the antioxidant enzymes were significantly (P<0.05) decreased in lead exposed subjects compared to controls while MDA levels were significantly (P<0.05) increased. Serum follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels were significantly (P<0.05) increased in lead exposed subjects compared to controls but testosterone levels remained the same in both lead exposed and control subjects. The study also revealed negative correlation between blood lead levels and reproductive hormones. In conclusion, environmental exposure to lead distorts antioxidant enzymes activity and male reproductive hormones levels perhaps via lead-induced oxidative stress. Key words: Lead exposure, oxidative stress, reproductive hormones.