Actions of Toxicants on the Structure and Function of the Epididymis

Abstract

There is increasing public concern regarding the possibility that semen quality might be declining in the human populaAmanntion due to environmental chemical and pharmaceutical exposures (Carlsen et al., 1992; Giwercman and Skakkebaek, 1992; Sharpe, 1993; Colborn et al., 1993; Auger et al., 1995; Comhaire et al., 1995; 1996; Menchini-Fabris et al., 1996; Pajarinen et al., 1997; Swan et al, 1997; Zorn et al., 1999; Gyllenborg et al. 1999). If future research establishes that this putative decline in semen quality is indeed occurring, and that chemical exposures are significantly associated with semen quality, the epididymis must certainly be considered a possible target organ. While historically the testis has been implicated with compromised sperm quantity and quality, it is important to remember that the epididymis is also pivotal in providing, through processes of sperm maturation such as plasma membrane modifications, sperm that are capable of fertilization (Bedford, 1975; Vreeburg et al., 1992; Klinefelter and Hamilton, 1985; Moore et al., 1987; Amann et al., 1993, Cooper, 2000). Moreover, sperm maturation within the epididymis may also be compromised by decreases in the epididymal transit time as the time available for processes requisite to the acquisition of fertility would be reduced. Finally, it should be recognized that in addition to possible qualitative effects of transit perturbations, the number of sperm available for ejaculation may also be influenced by transit rates.