The Cytoplasm: The Secretory System

Abstract

In their classical Nobel Prize–winning studies on protein biosynthesis and secretion, Palade and coworkers used the exocrine pancreas as a model tissue. The low-power electron micrograph from rat exocrine pancreas shows acinar cells and immunogold labeling for one of their major secretory products, the digestive enzyme amylase. As such, it provides a general idea of the main structural elements of the secretory pathway in a highly specialized secretory cell. The immunoelectron microscopic demonstration of intracellular antigens in ultrathin sections has been critically improved by the introduction of gold particles as a marker. The scheme shows the two-step protein A-gold technique to detect antigenic sites in ultrathin sections.