The formation of annulate lamellae in the human Sertoli cell.

The formation of annulate lamellae (AL) has been studied in human Sertoli cells. Sertoli cells of infants did not show AL. Sertoli cells of 9- to 11-year-old boys showed incompletely circumferentially arranged cisternae of endoplasmic reticulum (ER), alternating with rows of vesicles, 200-300 nm in diameter, with a weakly osmiophilic content. The ER cisternae displayed both pores and attached ribosomes at a few sites. These membranous structures were also observed beside true concentrically arranged AL in pubertal Sertoli cells (11-13 years of age). Both types of membranous formations were continuous with parallel, rough endoplasmic reticulum cisternae (RER) that interconnected them. Adult Sertoli cells showed only AL, not the other peculiar membranous formation. These features suggest that the RER plus associated vesicles originate the AL in human Sertoli cells.