Species differences in the testicular toxicity of phthalate esters.

Oral administration of di-n-butylphthalate (DBP) produced uniformly severe seminiferous tubular atrophy in rats and guinea pigs but caused only focal atrophy in mice. Hamsters showed no testicular changes with DBP and only minor changes in response to di-(2-ethylhexyl)phthalate (DEHP) and di-n-pentylphthalate (DPP). The rate of intestinal monohydrolysis of DEHP was slower in hamsters than in rats and this may be important, as mono-(2-ethylhexyl)phthalate (MEHP) did cause focal seminiferous tubular atrophy in hamsters. However, mono-n-butylphthalate (MBP) had no such effect. The decrease in testicular zinc concentration and enhancement of urinary zinc excretion produced in rats by DEHP and DPP was not observed in hamsters. Thus, species differ widely in their sensitivity to the testicular toxicity of phthalate esters.