Possible Origin of Rat Testicular Atrophy Induced by Di-n-Butyl Phthalate: Changes in the Activities of Some Enzymes during Rat Testis Perfusion under a Hypoxic Condition and with Mono-n-Butyl Phthalate

Abstract

To examine whether testicular toxicity in rats is caused by a direct effect of mono-butyl phthalate (MBP), a metabolite of di-butyl phthalate, or by a secondary effect attributed to a hypoxic condition due to the MBP-induced hemoglobin deprivation, the testes were perfused with a solution of MBP in Eagle's MEM or the MEM with/without oxygen, and the activities of testicular enzymes were measured. A decrease in the succinate dehydrogenase (SUDH) activity was observed by the hypoxic perfusate [20-30% dissolved oxygen (DO)], and an induction of apoptosis was observed by the 7% DO perfusate. However, the 100 mM MBP perfusate decreased the activity of SUDH per testis weight, but not per protein level. Therefore, this study proposes that the toxicity might be caused by hypoxia and a coincident depletion of SUDH activity, followed by an apoptotic testicular cell death.