Spermatogonia

Abstract

The earlier germ-cells in the adult testes are the spermatogonia, which are located in the basal compartment of the seminiferous epithelium, close to the basal lamina (Figs. 5 and 12). After a series of mitoses, the spermatogonia give rise to the spermatocytes. The spermatogonial cell divisions are usually incomplete. The daughter cells remain interconnected by cytoplasmic bridges. It generally is accepted that mouse spermatogonia undergo six successive divisions prior to the start of the prolonged meiotic prophase (Clermont and Bustos-Obregon 1968, Oakberg and Huckins 1976). The timing and spatial orientation of each of these mitotic multiplication steps is strictly regulated and can be distinguished from proliferative events in somatic cells by incomplete cytokinesis and the retention of wide intercellular bridges between germ-cells (Fig. 9) (Fawcett et al. 1959, Dym and Fawcett 1971, Schleiermacher and Schmidt 1973, Guraya 1980, Holstein and Roosen-Runge 1981, Kerr and de Kretser 1981). The junctions or desmosome-like structures occur between neighbouring spermatogonia (Holstein and Roosen-Runge 1981).