Anastrozole (ZD-1033) Anastrozole (ZD-1033) is a third-generation nonsteroidal selective aromatase inhibitor. It may offer greater selectivity compared with other aromatase inhibitors, being without any intrinsic endocrine effects and with no apparent e In vitro
Anastrozole has high intrinsic potency in vitro and inhibits human placental aromatase with an IC50 of 15 nM. Anastrozole it is 200 times as potent as AG, twice as potent as 4-OHA and one third as potent as fadrozole. . Anastrozole inhibits aromatase by binding competitively to the hem group of the CYP unit of the enzyme thereby reducing estrogen biosynthesis in the periphery and the breast. Anastrozole has little or no effect on other steroid hormones.
In vivo
Anastrozole (0.1 mg/kg) given orally to mature rats on Day 2 or 3 of the estrous cycle, blocked ovulation in mature females; in pubertal rats, the same dose given for 3 days completely blocks androstenedione-stimulated uterine development. These effects may be attributes to inhibition of the normal preovulatory rise in ovarian follicular estrogen synthesis in mature females and to inhibition of metabolism of the exogenous androstenedione by the immature ovary in prepubertal females. Twice-daily administration of >9.1 mg/kg of Anastrozole given orally to male pigtailed monkeys inhibits peripheral aromatase, thereby reducing circulating estradiol concentrations by 50% to 60%. Cell Data
