Mechanism of testicular atrophy induced by di-n-butyl phthalate in rats. Part 2. The effects on some testicular enzymes.

A single oral dose of di-n-butyl phthalate (DBP) to male rats caused histologically a sloughing of the germ cells at 6 h. On Days 1 and 2 more severe sloughing was seen, followed by atrophy and the dissociation of the germ cells from the Sertoli cells and the spermatogonia. Biochemically, there was elevation of gamma-glutamyl transferase, a decrease in sorbitol levels at 3 h and a decrease in the activity of aldose reductase at 6 h, in the testes of treated rats. This was followed by decreases in fructose levels and increases in the activity of lactate dehydrogenase (LDH) and in lactate levels at 12 h, and decreases in the activities of sorbitol dehydrogenase and succinate dehydrogenase on Day 2. LDH isoenzymes 4 and 5 increased at 6 h prior to the increase in lactate levels. Increases in the levels of inositol and the activities of alkaline phosphatase and lactate dehydrogenase were also observed. Thus, these data suggest that DBP-induced testicular toxicity is caused by a shortage of energy fuels from glucose metabolism or by an anoxia.