Cytoplasmic annulate lamellae and intranuclear membranes in human spermatids and sperm.

In human spermatide cytoplasmic annulate lamellae and intranuclear lamellae were found. In the cytoplasm, the annulate lamellae may vary from 3 to 11 layers of cisternal structures. There is evidence that the annulate lamellae are formed from the outer nuclear envelope. The intranuclear membranes are often seen directly connected to the inner nuclear membrane. These morphologic findings suggest that annulate lamellae may be involved in the transfer of genetic material from the nucleus to the cytoplasm.