ABSTRACT
A mindset similar to that for the microvesicles was at work for the mechanism of secretion itself. In the mid-19th century, the great German microscopic anatomist Rudolf Heidenhain noticed that under certain circumstances when pancreatic secretion was stimulated, the area of the acinar cell occupied by zymogen granules was markedly decreased. In the minds of many, and in many research papers, its presence was seen jointly both as proof of exocytosis and proof that this was the mechanism of secretion. The duct-facing surface of the acinar cell where the secretion of digestive enzymes into the intestines took place was not littered with omega figures as one might expect, especially in actively secreting glands. At another symposium, the creator of the vesicle model and soon-to-be Nobel Laureate gave a talk similar to mine about the mechanism of secretion by the acinar cell of the pancreas.
