PANETH CELL

The Paneth cell is the subject of considerable controversy and as yet a definitive role has not been ascribed to it. Much of the controversy is no doubt due to the way in which Paneth cells have been investigated. Interpretation of decreased or increased function based upon change in simple tinctorial reaction of the granules is clearly not scientific and the instability of the granules as evidenced by degranulation induced by acid fixatives adds another source of potential error. There are several instances in which attention to detail such as appropriate fixative have been overlooked and much of the discrepancy in studies concerning Paneth cell kinetics is due to poor methodology. The staining properties of the granules - for example, with phloxine-tartarazine - formed the basis of the major part of earlier experimental work. Clearly, increased granularity of the cells can be interpreted as due to either increased synthesis or blockade of secretion and reduced granularity to increased secretion or reduced synthesis. Estimating the numbers of Paneth cells solely on the basis of stainability of their granules is another obvious and significant source of error. With newer methods of investigation, which are based upon biochemical and immunochemical characteristics, real advances in the authors' knowledge of Paneth cell function can be expected soon. There seems to be no doubt that Paneth cells secrete a proteinaceous substance into the gut lumen and that this contains immunoglobulin and lysozyme. It is clear also that their secretion is intimately related to the small intestinal environment and not to that of the normal stomach and large intestine. When the intragastric and intracolonic environment changes, possibly acquiring similarities to that of the small intestine due to changes in pH and microbial flora, for example, then there is a metaplasia towards small intestinal epithelium including Paneth cells.