Methoxychlor, an organochlorine
pesticide, has been reported to induce reproductive abnormalities in male reproductive tract. To get more insight into the mechanism(s) of gonadal toxicity provoked by
methoxychlor, we investigated whether treatment with
methoxychlor at low observed adverse effect level (LOAEL) would alter the activities of steroidogenic
enzymes such as Delta(5)3beta-hydroxysteroid
dehydrogenase (3beta-HSD) and Delta(5)17beta-hydroxysteroid
dehydrogenase (17beta-HSD), the expression levels of steroidogenic acute regulatory (StAR)
protein and
androgen binding protein (ABP) in the testis of adult male rats. The experimental rats were exposed to a single dose of
methoxychlor (50 mg/kg
body weight) orally. The rats were killed at 0, 3, 6, 12, 24 and 72 h following treatment using
anesthetic ether and testes were collected, processed and used to measure the activities of 3beta-HSD, 17beta-HSD, levels of
hydrogen peroxide produced and the expression levels of StAR
protein, and ABP.
Methoxychlor administration resulted in a sequential reduction in the expression of StAR
protein and activities of 3beta-HSD, 17beta-HSD with concomitant increase in the levels of
hydrogen peroxide in the testis. These changes were significant between 6-12 h following treatment. The levels of ABP declined at 6-12 h following exposure to
methoxychlor. The present study demonstrates transient effect of
methoxychlor at LOAEL on testicular steroidogenesis and the possible role of
hydrogen peroxide in mediating these effects.