Effects of vitamins C and E on steroidogenic enzymes mRNA expression in polychlorinated biphenyl (Aroclor 1254) exposed adult rat Leydig cells

Disruption of LH-induced testosterone biosynthesis in testicular Leydig cells by triclosan: probable mechanism of action

Triclosan (TCS) is an antimicrobial chemical widely used in different commercial preparations. The present study demonstrated the mechanism of action of TCS-induced anti-androgenicity in rat Leydig cells. Treatment of purified cells with increasing concentrations of TCS (0.001, 0.01, 0.1, 1 and 10 microM) resulted in a significantly decreased activity of adenylyl cyclase enzyme which was followed by a decreased synthesis of cAMP. This decreased cAMP level resulted in the disruption of entire steroidogenic cascade causing a depressed synthesis of testosterone. However, TCS-induced decrease in the production of testosterone returned to normalcy when cells were treated with forskolin (an adenylyl cyclase activator). Transcription followed by translational of four prominent steroidogenic enzyme/proteins, cytochrome P450 side chain cleavage (P450scc), 3beta-hydroxysteroid dehydrogenase (3beta-HSD), 17beta-hydroxysteroid dehydrogenase (17beta-HSD) and steroidogenic acute regulatory (StAR) protein, also decreased in a dose-dependent manner in TCS-treated Leydig cells as determined by RT-PCR, enzyme assay and Western blot. These results suggested that the disruption of the activity of adenylyl cyclase enzyme by TCS in turn leads to the disruption of intermediate steroidogenic cascade causing a depressed testosterone production. The study further confirmed the anti-androgenic activity of TCS in Leydig cells with highest effective concentration at 1 microM.

Protective effects of dehydrocavidine on carbon tetrachloride-induced acute hepatotoxicity in rats

AIM OF THE STUDY

To investigate the protective effects of dehydrocavidine (DC), a main active ingredient of Corydalis saxicola Bunting (Yanhuanglian), on carbon tetrachloride (CCl4)-induced hepatotoxicity and the possible mechanisms involved in male Sprague-Dawley rats.

MATERIALS AND METHODS

Acute hepatotoxicity was induced by CCl4 intoxication in rats. Serum biological analysis, lipid peroxides and antioxidants estimation, histopathological studies were carried out.

RESULTS

Both pre-treatment with DC prior to CCl4 administration and post-treatment with DC after CCl4 administration significantly prevented increases in serum enzymatic activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and total bilirubin (TBIL). In addition, pre- and post-treatment with DC also significantly prevented formation of hepatic malondialdehyde (MDA), depletion of glutathione peroxidase (GPx) and depression of superoxide dismutase (SOD) in the liver of CCl4-intoxicated rats. ALT, AST, LDH, ALP and TBILL levels, as well as MDA, SOD and GPx activities were unaffected in normal rats by treatment with DC alone. GST, a phase II enzyme, had no significant changes during our experiments. Histopathological changes induced by CCl4 were also significantly attenuated by DC treatment in both preventive and curative experiments.

CONCLUSIONS

DC has a potent hepatoprotective effect on CCl4-induced liver injury in rats through its antioxidant activity.