Thiourea-induced alteration in the expression patterns of some steroidogenic enzymes in the air-breathing catfish Clarias gariepinus.

Previous study from our laboratory on thiourea-induced thyroid hormone depletion in mature male catfish demonstrated that thyroid hormones play a significant role in testicular function. In the present study, we aimed to analyze the changes in the expression pattern of several steroidogenic enzyme genes after thyroid hormone depletion using semi quantitative RT-PCR in both adult male and female catfish. There was a marked decrease in the 11beta-hydroxylase expression in the testis and liver while no change was observed in case of kidney. A significant decrease in 11beta-hydroxysteroid dehydrogenase transcript level in testis, liver and kidney were observed in the thiourea treated males. The results obtained corroborated with our earlier findings of testicular regression after thyroid hormone depletion. In females, expression of aromatase transcript increased in experimental group compared to control. There was no considerable change observed in the transcript level of 3beta-hydroxysteroid dehydrogenase, P450 17alpha-hydroxylase/C17-20-lyase, and 20beta-hydroxysteroid dehydrogenase in both males and females. Thus, thyroid hormones might exert modulating effect on steroidogenic enzyme genes at the transcription level.