Annulate lamellae and single-pore complexes in human spermatogonia.

Electron microscopic examination of non-neoplastic human testes revealed cytoplasmic annulate lamellae (AL) in all cell types within the seminiferous epithelium. Short lamellar profiles with low numbers of pores were found in spermatogonia and spermatocytes, while larger stacks of AL were seen in spermatids and Sertoli cells. Stacks of lamellae were closely associated with redundant nuclear envelope during late spermiogenesis. Residual bodies shed by the developing spermatozoa contained large number of lamellar-pore complexes. One cryptorchid testis was also examined. In this case the seminiferous epithelium consisted only of Sertoli cells with rare spermatogonia. AL were found in both cell types, with a similar morphology to those of the non-neoplastic testes. This study demonstrates that AL are expressed in all stages of spermatogenesis.