Gastric chief cell

A gastric chief cell (or peptic cell, or gastric zymogenic cell) is a type of cell in the stomach that releases pepsinogen and gastric lipase and is the cell responsible for secretion of chymosin in ruminants. The cell stains basophilic upon H&E staining due to the large proportion of rough endoplasmic reticulum in its cytoplasm. Gastric chief cells are generally located deep in the mucosal layer of the stomach lining.

Chief cells release the zymogen (enzyme precursor) pepsinogen when stimulated by a variety of factors including cholinergic activity from the vagus nerve and acidic condition in the stomach. Gastrin and secretin may also act as secretagogues.

It works in conjunction with the parietal cell, which releases gastric acid, converting the pepsinogen into pepsin.

Nomenclature

The terms chief cell and zymogenic cell are often used without the word "gastric" to name this type of cell. However those terms can also be used to describe other cell types (for example, parathyroid chief cells). Chief cells are also known as peptic cells.

Chief cell

In human anatomy, there are three types of chief cells, the gastric chief cell, the parathyroid chief cell, and the type 1 chief cells found in the carotid body.

Cell Types

A gastric chief cell (also known as a zymogenic cell or peptic cell) is a cell in the stomach that releases pepsinogen and chymosin. Pepsinogen is activated into the digestive enzyme pepsin when it comes in contact with acid produced by gastric parietal cells. This type of cell also secretes gastric lipase enzymes, which help digest triglycerides into free fatty acids and di- and mono-glycerides. There is also evidence that the gastric chief cell secretes leptin in response to the presence of food in the stomach. Leptin has been found in the pepsinogen granules of chief cells.

Gastric pit cells are replaced every 2–4 days. This high rate of turnover is a protective mechanism designed to protect the epithelial lining of the stomach from both the proteolytic action of pepsin and the acid produced by parietal cells. Gastric chief cells are much longer lived and are believed to differentiate from stem cells located higher in the gastric unit in the isthmus. These stem cells differentiate into mucous neck cells in the isthmus and transition into chief cells as they migrate towards the base. Since the mucus neck cells do not divide as it becomes a chief cell this process is known as transdifferentiation. The gene Mist1 has been shown to regulate mucus neck cell to chief cell transdifferentiation and plays a role in the normal development of the chief cell organelles and structures.