FIGURE 9.

Effects of fluid shear stress on leptin-mediated induced phosphorylation of JAK2 and STAT3 (A) and on the amounts of co-immunoprecipitated Jak2 and Stat3 with Lepr in B6 osteoblasts (B). In A, primary osteoblasts isolated from B6, ob⁻/ob⁻, and C3H mice were each treated with 100 ng/ml leptin with or without the 30-min steady fluid shear stress of 20 dynes/cm². Ten min after the shear stress, the stressed cells (St) and the corresponding static control cells (Con) were lysed in radioimmune precipitation buffer, and the relative levels of Tyr(P)-Jak2 and total Jak2 as well as those of Tyr(P)-Stat3 and total Stat3 were analyzed by Western blot. In B, immediately after the 30-min shear stress, cell extracts of the stressed and static control B6 osteoblasts were immunoprecipitated (IP) with anti-Lepr and blotted (IB) against anti-Jak2 (left) or anti-Stat3 (right).