Aconitine inhibits androgen synthesis enzymes by rat immature Leydig cells via down-regulating androgen synthetic enzyme expression in vitro

Aconitine might have reproductive toxicity and the effects of aconitine on androgen synthesis in Leydig cells remain unclear. Here, we explore how aconitine affects androgen synthesis and metabolism in rat immature Leydig cells in vitro. Immature Leydig cells were isolated from 35-day-old male Sprague Dawley rats and cultured with 0–50 μM aconitine for 3 h in combination with LH, 8Br-cAMP, 22R-hydroxycholesterol, pregnenolone, progesterone, androstenedione, testosterone, and dihydrotestosterone, respectively. Medium androgens were measured. The levels of Leydig cell mRNAs, Lhcgr, Scarb1, Star, Cyp11a1, Hsd3b1, Cyp17a1, Hsd17b3, Srd5a1, and Akr1c14, were measured by qPCR. ROS and apoptosis were determined after 24-h aconitine treatment. Aconitine inhibited basal androgen production in Leydig cells at 0.05 μM and the higher concentrations. Aconitine blocked pregnenolone, progesterone, and androstenedione mediated androgen outputs without affecting 22R-hydroxycholesterol-mediated androgen production at 5 μM. Aconitine also inhibited LH and 8Br-cAMP stimulated androgen outputs at 5 μM. Further investigation showed that aconitine blocked androgen synthesis via down-regulating the expression of Scarb1, Hsd3b1, Cyp17a1, and Hsd17b3. At 50 μM, aconitine also induced ROS generation and increased apoptotic rate of Leydig cells. Aconitine lowered serum testosterone levels at 1.5 mg/kg after 7 days of oral exposure from postnatal day 35. In conclusion, aconitine inhibits androgen synthesis.