Three-dimensional ultrastructure of the Golgi region of the formative chondrocyte in newborn rat mandibular condyle.

The three dimensional ultrastructure of Golgi region of formative chondrocytes from newborn rat mandibular condyle was examined by means of the method based on dilute osmium maceration with a high-resolution scanning electron microscope. The large area of formative chondrocytes was occupied by the cytoplasmic organelles related to matrix-synthesis such as Golgi apparatus, rough endoplasmic reticulum (RER) and mitochondria. The Golgi region of formative chondrocytes was composed of the limiting membranous structures such as some groups of the stacks of Golgi cisterns, vesicles, vacuoles, secretory granules, reticular constituents and small tabular or tubular RER. The Golgi cisterns were composed of both small tabular parts and rod-like parts arising from tabular parts. Small tabular parts were furthermore subdivided into three types of many, few and no penetrated ones. Reticular constituents were made up of limiting membrane visible as smooth image by scanning electron microscopy, therefore, are assumed to be one part of the GERL (Golgi apparatus-endoplasmic reticulum-lysosome).