ABSTRACT
This chapter discusses the effect of toxic agents in the adult, it should be appreciated that substances may interfere with the early stages of sexual differentiation, either morphologically (formation of germ cells, genital tract) or behaviorally (brain development). A direct effect of toxic chemicals on the haploid germ cell of the testis demands that the toxin crosses the blood-testis barrier to enter the adluminal compartment of the seminiferous tubule containing the more advanced stages of sperm development. Thus, important toxic effects in the testis could result from relatively low initial doses of chemical. Conversely, foreign substances may be bound to macromolecules on entering the bloodstream, inhibiting their entry across the blood-testis barrier. This toxicity is due to a stereospecific inhibition of sperm glycolysis, the active agent being the s-enantiomer of a-chlorohydrin, which, probably due to its structural similarity to glycerol, is a competitive inhibitor of sperm glycerol kinase.
