The expression patterns of FGFR1, FGFR2, and FGFR3 on postnatal day (pnd) 20 in mice testis. The expression patterns of FGFR1 (A and B), FGFR2 (C and D), FGFR3 (E and F), and FGFR4 (G and H) on pnd 20 mice testis were detected using immunohistochemistry. Control sections without a primary antibody treatment are arranged on right side of the figure (I and J). The long arrow indicates the cell types as illustrated by the abbreviation: MCs, myoid cells; SCs, Sertoli cells; Sg, spermatogonia; and Sc, spermatocyte. Scale bar = 50 µm (200 ×) and 19 µm (400 ×).