One possible explanation is that fenitrothion can alter the activity of aromatase, which then alters the level of estrogens converted by it from androgens and finally alters the volume of SDN-POA.
A potential cause for this phenomenon could be that fenitrothion influences the function of aromatase, leading to a change in the conversion rate of androgens into estrogens, which subsequently alters the quantity of SDN-POA produced.