ABSTRACT
Alpha 1-antitrypsin (alAT) is one of the most abundant serine protease inhibitors present in the bloodstream of mammals. As with to many serum proteins, the major site of a 1 AT synthesis is the liver, from which it is secreted into the plasma (1). In the blood circuit, alAT exerts its inhibitory action on plasma proteases. Other sites displaying a lower degree of a 1 AT expression are the kidney, lung, and small intestine, where additional localized action is required (2-4). In the lung, alAT acts to protect the tissue from hydrolytic destruction by excessive neutro phil elastase (NE) (5-7). The physiological role of alA T expression in the kidney is still unclear. In contrast, because it is capable of inactivating several pancreatic digestive enzymes, it has been postulated that gastrointestinal alAT modifies protein digestion when secretion of digestive enzymes is reduced, as in the case of pancreatic insufficiency (4). A severe deficiency of alAT in serum is associated with chronic liver disease and premature development of pulmonary emphysema (8). alAT also belongs to a family of proteins called acute-phase reactants because their rate of synthesis is modified in response to inflammation. Its concen tration in serum increases three-to four-fold following inflammation or tissue injury (9).
