Testicular atrophy induced by di(2-ethylhexyl)phthalate: changes in histology, cell specific enzyme activities and zinc concentrations in rat testis

Daily administration of 2g/kg/day di(2-ethylhexyl)phthalate (DEHP) to immature rats was found to cause testicular atrophy and reduce zinc concentration. Specific activities of testicular enzymes associated with postmeiotic spermatogenic cells, such as lactate dehydrogenase isozyme-X, hyaluronidase and sorbitol dehydrogenase, were lower than those of control by day 10, coincident with degeneration of spermatogenic cells. The specific activities of enzymes associated with premeiotic spermatogenic cells, Sertoli cells or interstitial cells (beta-glucuronidase, gamma-glutamyl transpeptidase and malate dehydrogenase) were higher than those of control by day 10. The specific activities of alcohol dehydrogenase and aldolase, zinc containing enzymes, increased after DEHP treatment in spite of the decrease in zinc concentration in the testis. In conclusion, changes in several testicular cell-specific enzymes appear to be useful biochemical markers of testicular injury induced by testicular toxicants such as DEHP. However, these changes occurred after or simultaneous with massive histological or morphological changes rather than prior to such changes.