Electron micrographs of portions of seminiferous tubules of rats from CmG. In A, the irregular outlined tubule shows SC nucleus with normal aspect (S) and evident nucleolus (black arrowhead). Mitochondria with tubular cristae (Mi), smooth endoplasmic reticulum (Ser) and lipid inclusion (Li) are observed. Portions of the epithelial basal lamina are thickened (Bl). The layer between the myoid cell (M) and Bl is also thickened and shows numerous type I collagen fibrils (asterisk). The SC plasma membrane is adhered to the lamina densa by hemidesmosome-like junctions (white arrowheads). ×11,700. In B, the basal lamina (Bl) surrounding the irregularly outlined tubule is infolded. Adjacent to both inner and outer surfaces of the myoid cell (M), continuous and infolded basal laminae are observed (Bli and Ble). Between Bl and Bli, a thick layer with type I collagen fibrils (asterisks). Portions of the SC plasma membrane containing hemidemosome-like junctions are detached from the Bl (white arrowheads) and surrounded by a thin lamina of amorphous matrix (inset; arrowhead). In the SC, mitochondria (Mi) and filaments of the cytoskeleton (black arrows) are observed. In the nuclear periphery, electron dense clumps of chromatin are observed (white arrows). ×10,000. Inset: ×13,300.