Angiotensin converting enzymes from human urine of mild hypertensive untreated patients resemble the N-terminal fragment of human angiotensin I-converting enzyme.

Angiotensin I-converting enzyme (ACE) activity was analyzed in human urine collected from mild hypertensive untreated patients. DEAE-cellulose chromatography using linear gradient elution revealed two forms of angiotensin I-converting enzyme, eluted in the conductivity of 0.75 and 1.25 mS. The fractions of each conductivity were pooled and submitted to direct gel filtration in an AcA-34 column, and the apparent molecular weights of urinary ACEs were estimated as 90 kDa (for ACE eluted in 0.75 mS) and 65 kDa (for ACE eluted in 1.25 mS). Both enzymes have a K(i) of the order of 10(-7) M for the specific inhibitors studied, and are able to hydrolyze luteinizing hormone-releasing hormone and N-acetyl-Ser-Asp-Lys-Pro as described for N-domain ACE. By Western blot analysis, both peaks were recognized by ACE-specific antibody Y4, confirming the molecular weight already described. A plate precipitation assay using monoclonal antibodies to the N-domain of ACE showed that both forms of ACE binds with all monoclonal antibodies to the active N-domain ACE, suggesting that these forms of human urine ACEs resemble the N-fragment of ACE. The HP2 ACE (65 kDa) is similar to low molecular weight (LMW) ACE from normal subjects, and the HP2 ACE (90 kDa) is different from high molecular weight (190 kDa) and LMW (65 kDa) normal ACEs. The 90 kDa ACE could have an important role in development of hypertension. It will be fundamental to elucidate the molecular mechanism responsible for the genesis of this isoform.

[Lovastatin in the treatment of hypercholesterolemia in non-insulin-dependent diabetes mellitus patients]. / A lovastatina no tratamento da hipercolesterolemia em portadores de diabete não dependente de insulina.

PURPOSE: To evaluate the effects of lovastatin as an hypocholesterolemic agent in non-insulin dependent diabetic (NIDDM) patients with high cholesterol plasma levels. METHODS: Twenty NIDDM patients were included in this study. Hypercholesterolemia was defined as LDL-cholesterol plasma levels above 160mg/dl in female patients and above 130mg/dl in male patients or in women presenting any other risk factor for cardiovascular disease. From the 20 patients included, 18 had also high levels of arterial blood pressure. They were evaluated for admission in the study after they have substituted the antihypertensive medication for at least 6 weeks, from beta-blockers or diuretics to angiotensin converting enzyme inhibitors or calcium channel blockers. Lovastatin was administered in a initial daily dose of 20mg to all patients for 6 weeks. After this period this dose was increased to 40mg in 11 patients with LDL-cholesterol levels above 130mg/dl. All patients were treated for a total period of 24 weeks. RESULTS: Lovastatin therapy for 24 weeks reduced LDL-cholesterol and total cholesterol plasma levels in 30% and 21%, respectively, while no changes in HDL-cholesterol or triglycerides plasma levels were observed. The medication was well tolerated and no changes in bilirrubins or transaminases plasma levels were detected. In 9 patients the serum levels of alkaline phosphatase showed an elevation and the mean level of all group increased from 109 +/- 59 to 188 +/- 60m mu/ml (p < 0.05). This was an isolated abnormality without any other clinical manifestation. CONCLUSION: Lovastatin in NIDDM showed to be an efficient agent to reduce high levels of LDL-cholesterol and total cholesterol. However, the importance of the abnormality observed in serum alkaline phosphatase levels deserves further investigation. In this condition we recommend discontinuation of lovastatin therapy.

Hypokalemia, glucose intolerance, and hyperinsulinemia during diuretic therapy.

Hypokalemia and glucose intolerance may result from diuretic therapy. Increases in plasma insulin and glucose levels have been observed in thiazide-treated hypertensive patients and have been attributed to a diminished insulin sensitivity induced by diuretic therapy. To investigate the effects of hypokalemia on glucose tolerance and insulin secretion, we studied 21 essential and nine diabetic hypertensive patients after 4 weeks of placebo and after 4 weeks of chlorthalidone therapy (25 mg/day). Plasma glucose and insulin levels were measured for a 3-hour period after a 75-g glucose oral dose. Hypokalemia developed in seven of the essential hypertensive patients (HK group), whereas only one diabetic patient had decreased plasma potassium levels to below 3.5 meq/l. The results obtained in the HK group after chlorthalidone showed that plasma glucose and insulin values increased after the oral glucose load to levels significantly higher than those observed after placebo. In contrast, the patient who remained normokalemic after chlorthalidone did not show any change in plasma insulin and glucose levels during glucose tolerance testing. These results show that diuretic therapy may induce hyperglycemia and hyperinsulinemia and suggest that potassium depletion is involved in the increase in insulin resistance that has been demonstrated during thiazide therapy.