[Serum angiotensin converting enzyme in patients with primary liver carcinoma].
Recent studies have shown that serum activity of angiotensin-converting enzyme (ACE; EC 3.4.15.1) significantly decreases in patients with carcinoma of different localizations. There is no information in literature about measuring this enzyme in primary liver carcinoma patients. The serum activity of ACE has been examined on 15 primary liver carcinoma patients, 10 patients with cirrhosis, and 26 healthy subjects. Serum activity has been determined by spectrophotometric method using synthetic substrate Hip-His-Leu. The results were given in units which correspond to one nmol of hippuric acid released by enzymatic hydrolyze of Hip-His-Leu substrate in one minute on serum milliliter. The results have shown that serum activity of ACE increased in patients with cirrhosis (37.06 +/- 2.9; X +/- SEM; p < 0.05), and decreased in primary liver carcinoma patients (23.44 +/- 1.87; p < 0.01), what was statistically significant in comparison with the activity of the same enzyme in healthy subjects (29.90 +/- 2.72). These results point out the possibility of clinical application of measuring serum ACE activity as one of primary liver carcinoma marker in differential diagnosis of the disease.