Fig. 10. Estrogen influences Stat3 levels and activity in vitro and in vivo.

Addition of estradiol (E2) to female (a) and male (b) pig chondrocytes resulted in dose-dependent increases in Stat3 levels and activity; female chondrocytes are dose-limited in their response to E2 as evidenced by similar induction at the 0.1 and 1.0 µM doses. n = 3. c Intra-peritoneal Injection of Letrozole, an aromatase inhibitor that blocks the production of estrogen, reduced Stat3 levels and activity in female mouse sternal chondrocytes after 7 daily injections. n = 5 mice per group.