Chief cell

Gastrin G cells in pyloric region of the stomach Protein in stomach vagal stimulation Stimulates parietal cells (HC1) and chief cells (pepsinogen) in stomach enhances gastric motility... 

Pepsinogen is produced by the chief cells. Within the lumen of the stomach, this precursor molecule is split by HCl to form the active enzyme pepsin. Optimally active at an acidic pH (pH = 2), pepsin begins protein digestion by fragmenting proteins into smaller peptide chains. 

Gastrin is a hormone produced by gastric endocrine tissue — specifically, the G cells in the pyloric gland area. It is released into the blood and carried back to the stomach. The major function of gastrin is to enhance acid secretion by directly stimulating parietal cells (HC1) and chief cells (pepsinogen). Gastrin also stimulates the local release of histamine from enterochromaf-fin-like cells in the wall of the stomach. Histamine stimulates parietal cells to release HC1. 

Protein (long peptide chain) Pepsin Fragment proteins into smaller peptides Stomach chief cells Stomach... 

Leblond, C.P. and Messier, B. (1958) Renewal of chief cells and goblet cells in the small intestine as shown by radioautography after injection of thymidine-H3 into mice. Anatomical Record 132, 49—58. 

Gastric juice is the product of several cell types. The parietal cells produce hydrochloric acid, chief cells release pepsinogen, and accessory cells form a mucin-containing mucus. 

Xie G et al Cholinergic agonist-induced pepsinogen secretion from murine gastric chief cells is mediated by Mi and M3 muscarinic receptors. Am J Physiol 2005 289 G521. 

Pepsinogen secretion from gastric chief cells Cholinergic vasodilatation in cerebral vessels... 

M. S. Legator2-3 (treasurer) 44 FDA Chief, Cell Biology Branch Biochemistry, Bacteriology Mutagenicity studies Microbial genetics... 

Secreted by the chief cells of stomach as the zymogen. h Secreted by the pancreas as the zymogen. 

The stomach environment is acidic as a result of HC1 secretion by the parietal cells. The acidic pH serves to denature many proteins, thus making them susceptible to proteolysis. The chief cells of the stomach produce pepsinogen, which is activated to pepsin by the HC1 (see Table 20.3). The optimum pH of peptic activity is around 2, and pepsin is inactivated at neutrality. Another stomach enzyme is rennin or chymosin, which is present in infants but not in adults. It removes a glycopeptide from milk-K-casein, disrupting the casein micelle and promoting milk protein coagulation and digestion. 

Chief cells in the parathyroid gland synthesize, store, and secrete PTH. PTH is synthesized as a pre-pro PTH precursor. The pre- and prosegments are cleaved enzymatically during... 

The entry of protein into the stomach stimulates the release of a hormone, gastrin, which then causes the release of hydrochloric acid from the parietal cells, and pepsinogen from the chief cells (Fig. 15-5). Pepsinogen is another zymogen (they all start with pro- or end in -ogen) that is converted in the gastric juice to the active enzyme pepsin. 

Distal renal cells Parathyroid gland (chief cells)... 

Pepsinogen is secreted by chief cells in the gastric mucosa and is the precursor of the protease enzyme pepsin. 

Gastric parietal cells and chief cells have low permeability to protons, preventing back-diffusion of acid. 

Gelatinase is a separate proteolytic enzyme, since it liquefies gelatin about 400 times faster than pepsin does. It is probably derived from chief cells and has been thoroughly studied by Northrop (NlOa). 

Another antibody was experimentally produced in rabbits by injecting pepsin (G5). It was detected by the Ouchterlony technique and precipitation reactions, and may have some clinical significance in producing atrophy of chief cells. Repeated injection of this immune serum into rats also caused decrease in the volume of gastric juice, with lower concentrations of acid and pepsin. The controls injected with antibodies to egg albumin, nonspecific globulins, and saline did not show similar changes (see Fig. ). 

The oxyntic gland is the secretory unit of the gastric mucosa. The acid-secreting parietal cells are located in the wall of its midsection. In addition to parietal cells, these glands consist of mucous-secreting superficial and neck cells, pepsinogen-secreting chief cells, endocrine, and somatostatin cells [1]. 

Entry of protein in to stomach stimulates gastric mucosa to secreate the hormone gastrin. Which stimulates the secretion of hydrochloric acid by the parietal cells of gastric glands and pepsinogen by the chief cells. 

Gastrin affects the motility, or movement of the stomach and appears to cause the chief cells to secrete pepsin. However, the chief cells respond to a number of different stimuli, and no single stimulant has been found to be of primary importance. 

A species difference should be noted- Intrinsic factor is produced by the parietal cells in humans, rabbits, cats, monkeys, and guinea pigs, but by the chief cells and parietal cells in rats, and by mucous cells and parietal cells in hogs. 

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