This is common for secretion of digestive enzymes. These hormones influence stomach activities in a variety of ways. For example, gastrin helps to regulate secretions from the other gastric glands. To protect the stomach a mucosal barrier exists. This is not the same hormone as the renin from the kidneys.
Pepsinogen is converted to the active protein digesting form, pepsin.
This conversion is aided by the low pH of 1-3, which is due to the HCl secreted by specific stomach mucosal cells. Food and liquid are mixed with stomach secretions to form acidic chyme . Chyme is squirted into the duodenum of the small intestine through the pyloric sphincter . Some absorption occurs in the stomach. The stomach absorbs relatively few substances and these are absorbed in small amounts.