Effects of polychlorinated biphenyl-containing and -free transformer fluids on testicular enzyme activities

Abstract

The frequently used polychlorinated biphenyl-based dielectric fluids have been gradually substituted with mineral fluids because of their toxic activities observed in many vertebrate tissues. Here we compared the acute in vivo effects of Pyralene, an Aroclor 1260-based transformer fluid, with a sample of mineral oil called ENOL C on the activities of the four rat testicular antioxidant enzymes, superoxide dismutase, glutathione transferase, catalase and glutathione peroxidase, and three steroidogenic enzymes, 3β-hydroxysteroid dehydrogenase, 17α-hydroxylase/lyase, and 17β-hydroxysteroid dehydrogenase. The activities of these enzymes were estimated 2 h and 24 h after bilateral intratesticular (25 μg/testis) injection of Pyralene and ENOL C. Short-term treatment with these compounds did not affect any of the enzymes studied. ENOL C was also ineffective during 24 h exposure, whereas Pyralene inhibited glutathione transferase and stimulated catalase and glutathione peroxidase in testicular interstitial cells. This was accompanied with the inhibition of 3β-hydroxysteroid dehydrogenase activity and a small increase in 17α-hydroxylase/lyase activity. These results indicate that the 24-h of intratesticular exposure to Pyralene was sufficient to detect its toxic effects on testicular enzymes, whereas ENOL C was ineffective.