ABSTRACT
This chapter focuses on discussion of the vesicle theory on experimental observations. For the vesicle theory, the answer is “no.” This will no doubt come as a big surprise to many. Nonetheless, the fact remains that the theory fails on prima facie grounds. The rate at which cells successfully make substances must perforce equal their average rate of transfer to the site or sites of their action, such as being secreted. For instance, for the mechanisms imagined in the vesicle theory, every step from capturing the material in a forming vesicle, to the movement of the vesicle from place to place, to its fusion to a recipient compartment, to its release into that compartment, back to its budding from it, must equal the rate of synthesis. There is also a less fundamental, but no less challenging problem for secretion by the acinar cell of the exocrine pancreas by vesicle processes. The acinar cell secretes 10–20 different digestive enzymes.
