Pubertal exposure to tebuconazole increases testosterone production via inhibiting testicular aromatase activity in rats.

Tebuconazole is a triazole compound used agriculturally to treat plant pathogenic fungi. However, whether pubertal exposure to tebuconazole affects Leydig cell development remains unknown. Here, we exposed male Sprague-Dawley rats at 35 days of age to 0, 25, 50, or 100 mg kg-1 day-1 tebuconazole for 21 days. Tebuconazole exposure increased serum testosterone level but lowered estradiol level at a dose of 100 mg kg-1, without affecting serum luteinizing hormone and follicle-stimulating hormone concentrations. Tebuconazole up-regulated the expression of testicular Cyp11a1, Hsd11b1, and Fshr genes as well as their proteins at a dose of 100 mg kg-1. However, tebuconazole did not stimulate the proliferation of Leydig cells. Tebuconazole in vitro inhibits aromatase activity in primary rat Leydig cells with IC50 value of 40 μmol/L. In conclusion, tebuconazole exposure stimulates pubertal Leydig cell differentiation via inhibiting aromatase activity.