Aromatase Inhibitors Combined with Growth Hormone: A Cost-effective Last Chance for Improving Boys’ Stature at the Near-End of Growth?

Two studies have recently shown a clear benefit of using nonsteroidal aromatase inhibitors (AIs) in combination with growth hormone (rhGH) in pubertal boys of very short stature (between -2.5 and 3 SDS) who are approaching the end of their growth [1,2]. AIs have been used in human therapeutics since the 1990s, mostly in adults [3], to block aromatase by binding to the heme iron of aromatase, a cytochrome p450 enzyme that catalyzes the formation of C18 estrogens (estrone and estradiol) from C19 androgens (androstenedione and testosterone) [4]. In males, circulating estradiol is derived from direct testicular secretion (20%) and from peripheral conversion of adrenal or testicular androgens [5,6].