A three-dimensional study of organelle interrelationships in regenerating rat liver. 1. The Gerl-system.

Arguments are put together indicating that the GERL-system, or at least its thick membrane and part of its content are derived from the mature Golgi cisterna. Just like every Golgi cisterna does, the GERL shows direct continuities with ER, from which a complement of products may be supplied. Rigid lamellae are interpreted as intermediate forms in the transformation of the mature Golgi cisterna into the GERL-system. In hepatocytes the GERL produces two types of lysosomes: dense bodies, which may either contain lipoprotein granules or not, and small coated vesicles. The probable meaning of lipoprotein digestion (crinophagy) is discussed.