1) Unactivated secretin 
Prosecretin is a precursor to the chemical secretin, which is present in digestion. Secretin is stored in this unusable form, and is activated by gastric acid in the lower intestine to neutralize the pH and ensure no damage is done to the small intestine by the aforementioned acid. ...
Unactivated secretin. ... (05 Mar 2000) ... 
(pro″se-kre´tin) the precursor of secretin, found in epithelial cells of the intestine.
Type: Term Pronunciation: prō′sē-krē′tin Definitions: 1. Unactivated secretin.