Three‐dimensional architecture of the Golgi apparatus in Sertoli cells of the rat

Abstract

Glutaraldehyde‐fixed testes were stained “en bloc” with the Ur‐Pb‐Cu technique of Thiéry and Rambourg ('76) or post‐fixed and stained with the osmium tetroxide‐potassium ferrocyanide method of Karnovsky ('71). Thin or thick (up to 3 μm) sections were examined with the Philips (301 or 400) EM or the high voltage EM. Stereopairs were prepared with photographs of tilted specimens (± 7°). At low magnification, in thick sections (0.5–3 μm) stained with Ur‐Pb‐Cu, the whole Golgi apparatus formed a single network of interconnected wavy ribbon or platelike structures extending from the juxtanuclear region toward the apex of the cell. At higher magnifications, with the two staining techniques, this Golgi network showed two distinct types of regions: the “saccular region” corresponding to the conventional stack of saccules and the “intersaccular connecting region” made up of anastomotic tubules which bridge adjacent stacks. In the saccular regions, there was, on the cis‐face of the stack, a tight polygonal meshwork of anastomotic tubules (osmiophilic element). Underlying it there were three to seven closely apposed saccules perforated with pores of various diameters, and finally, on the trans‐face, a network of tubules was usually connected to the last saccule of the stack, which seemed to peel off from the pile, The intersaccular connecting regions showed proximal and distal zones with regard to the associated stacks. The proximal zone was made up of superimposed and parallel polygonal networks of membranous tubules which were continuous with corresponding saccules of the stack. In the distal zone they interdigitated, intertwined, anastomosed and bridged adjacent saccular regions; others turned at right angles and established connections with tubular extensions arising at various levels of the same stack. While cisternae of endoplasmic reticulum were contiguous with tubules or saccules located on the transface of the Golgi apparatus, a close association between the ER cisternae and the cis‐face of the stacks was not usually observed.