Tren is notorious for negatively impacting endurance and causing insulin resistance lasix and calcium levels Calcitriol decreases the expression of aromatase, the enzyme that catalyzes estrogen synthesis selectively in BCa cells and the breast adipose tissue surrounding BCa, by a direct repression of aromatase transcription via promoter II as well as an indirect effect due to the reduction in the levels and biological activity of PGE 2, which is a major stimulator of aromatase transcription through promoter II in BCa