Perinatal exposure to lead alters male reproductive behaviour and immunoreactivity of androgen and oestrogen receptors in the brain

Abstract

Lead (Pb) exposure during perinatal development alters testosterone (T) concentrations and delays puberty in children and laboratory rodents. In addition, exposure to the metal during adult life decreases T and libido in men and affects male reproductive behaviour (MRB) in rats. MRB is regulated by various brain nuclei including the medial preoptic area (MPOa) and the medial amygdala (MeA), in which T and oestradiol (E2) act through their respective androgen (AR) and oestrogen (ER) receptors. However, the mechanism by which MRB is affected by Pb exposure is not known. The objectives of the present study were to evaluate whether perinatal Pb exposure affects MRB and the number of cells immunoreactive to AR and ER alpha in the MPOa and the MeA. Male Wistar rats exposed to Pb (320 ppm) in drinking water from the beginning of pregnancy until weaning were used. The experimental group experienced significant alterations in MRB, an important decrease in T and E2 concentrations, and a significant increase in Pb concentrations in the blood, MPOa (hypothalamus) and MeA. In addition, in the studied areas the number of cells immunoreactive to AR and ER alpha, or detected using the Nissl technique, decreased significantly. These results show that perinatal exposure to Pb alters MRB. This event may be related to a decrease in both the concentrations of sex hormones and the number of cells that express their receptors as well as in the neuronal Nissl staining population. This ultimately affects the quality of life of the individual.