Low proliferation rate of the primordial germ cells in the anterior part of the testis. Data are from a 1-year-old male. (a), (c) and (e) show immunostaining; (b) and (d) show hematoxylin-eosin-light green staining of the sections shown in c and e respectively. (a), primordial germ cells in the anterior part of the testis are stained with the anti-PCNA antibody. (c), these cells do not incorporate BrdU. (e), (a) lobule at the anterior part of the first lobe, showing the synchronous proliferation of spermatogonia in a cyst attested by BrdU incorporation. Cy = Cyst, ED = efferent duct, Lo = lobule, LoC = lobule centre, PGC = primordial germ cells, SC = somatic cell.