Effects of endocrine disrupting heavy metals on pituitary and gonadal hormones in normal weight automechanics in Ibadan, Nigeria

Abstract

Association of hypogonadism and visceral obesity (VO) was recently demonstrated in male auto-mechanics occupationally exposed to endocrine disruptors (ED)-lead, cadmium, mercury and arsenic, known to alter the hypothalamic-pituitary-testicular axis. The effects of exposure to these EDs on pituitary and gonadal hormones in normal weight auto-mechanics in Ibadan were investigated. Ninety-nine normal weight male adults without any metabolic syndrome component-elevated VO, blood pressure, tryglycerides, fasting plasma glucose (FPG) and reduced high density lipoprotein cholesterol (HDLC), enrolled into this prospective cross sectional study. They were 50 auto-mechanics, age and anthropometry matched with 49 eugonadic males (occupationally unexposed to EDs) in Ibadan (control). Demography, lifestyle, sexual and reproductive history, anthropometery and blood pressure were obtained by standard methods. Fasting blood (15 mL) obtained was used for biochemical analyses-hormones (follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin, oestradiol and testosterone) by ELISA; EDs-Lead, cadmium, mercury and arsenic by AAS; FPG, HDLC, triglycerides and oxidative stress (OS) biomarker-total antioxidant capacity (TAC) by spectrophotometry. Data obtained were statistically significant at P<0.05. Only 45 (90%) auto-mechanics were eugonadic. EDs except arsenic were significantly higher while libido and TAC level were significantly lower in the auto-mechanics compared with control (P<0.05). In automechanics only, lead had an inverse relationship with testosterone (P= 0.001) but direct relationship with FSH (P= 0.013). LH had a direct relationship with mercury (P= 0.031) but indirect relationship with TAC (P<0.001). Auto mechanics may be occupational exposed to lead, cadmium and mercury with the induction of oxidative stress and testicular dysfunction.

Keywords: Heavy Metals, Hypogonadism, Metabolic Syndrome, Total Antioxidant Capacity, Testosterone