Figure 1.

PTHrP induces stem Leydig cell differentiation in vitro. Scheme of stem Leydig cell culture for 21 days (A). Staining of Leydig cells using CYP11A1 in the cross sections of the seminiferous tubules after 14 days in the ITS medium (B) and LH+ITS+LI medium (D). α-SMA (SMA, red color) was used to label peritubular myoid cells and CYP11A1 (green color, white arrow) was used to label Leydig cells. Medium testosterone levels after 14 days in ITS, LH, LI, and ITS+LH+LI (C), ITS+LH+LI together with various concentrations of PTHrP (E) as well as 1,000 pg/ml PTHrP with or without H-89 (1 μM) or U73122 (U, 1 μM) (F). Mean ± SEM, n = 6, ^*P < 0.05, ^**P < 0.01, ^***P < 0.001 when compared to the control.