AIMTo establish a method for determinate of the inhibitory activity of angiotensin-converting enzyme inhibitor captopril by high performance capillary electrophoresis.

METHODSThe characteristic absorptive wavelength of hippuric acid determined by ultraviolet spectrophotometer is 228 nm. The method employed a melted capillary column, 50 mmol.L-1 phosphoric acid (pH 8.3) buffer solution, inject pressure 4.8 kPa, inject time 3 s, separation voltage 20 kV and detection wavelength 228 nm.

RESULTSThe reactant and resultant was separated completed within 7 min. IC50 of captopril was 0.019 mumol.L-1. Captopril is a competitive inhibitor, which was proved by enzyme reaction dynamics.

CONCLUSIONThe method was shown to be accurate, simple and rapid and can be used for determination of the inhibitory activity of captopril.

Angiotensin-Converting Enzyme Inhibitors ; pharmacology ; Captopril ; pharmacology ; Electrophoresis, Capillary ; methods ; Hippurates ; analysis ; Peptidyl-Dipeptidase A ; metabolism

Angiotensin converting enzyme (ACE, EC 3.4.15.1) is a membrane-bound, zinc dependent dipeptidase that catalyzes the conversion of the decapeptide angiotensin I to the potent vasopressor ocatapeptide angiotensin II, by removing two C-terminal amino acids. ACE is well known as a key part of the renin angiotenisn system that regulates blood pressure, and its inhibitors have potential for the treatment of hypertension. This paper reviewed the characteristics of ACE in aspects of its structure-function relationship, gene polymorphism and inhibitor development. In particular, the catalytic mechanisms of the two active sites of somatic ACE in the cleavage of angiotensin I and bradykin are different. Therefore, it would likely provide a new way for exploiting novel ACE inhibitors with fewer side-effects by specifically-targeting the individual active sites of somatic ACE.
Angiotensin-Converting Enzyme Inhibitors ; pharmacology ; Antihypertensive Agents ; pharmacology ; Humans ; Peptidyl-Dipeptidase A ; chemistry ; genetics ; metabolism ; Polymorphism, Genetic ; Structure-Activity Relationship

OBJECTIVE: To investigate the correlation between the carotid artery plaque and the change of plasma aldosterone level related indexes during captopril challenge test. METHODS: The patients with hypertension were enrolled as research objects and the captopril challenge test were carried out when they were hospitalized to screen the cause of hypertension. There were intact carotid artery duplex ultrasonography diagnostic data in them (83 cases). They were divided into the plaque group(57 cases) with carotid artery plaque and no plaque group( 26 cases) without carotid artery plaque according to the carotid artery duplex ultrasonography diagnostic data. The correlation between the carotid artery plaque and the changes of aldosterone concentration, renin activity and aldosterone to renin activity ratio(ARR) in two groups were analyzed. RESULTS: The detection rate of carotid artery plaque was 68.67%. Compare with no plaque group, the patients in plaque group were elder and the level of apolipoprotein A1,(APOA1) was lower (all P＜0.05). The ARR difference value before and after captopril challenge test was lower ( P＜0.05).The aldosterone difference value and the renin activity difference value before and after captopril challenge test were higher in plaque group (all P＜0.05).The aldosterone difference value and the renin activity difference value were positive in plaque group and were negative in no plaque group. The difference value of the ARR was negative in plaque group and was positive in no plaque group. Logistic regression analysis showed that the age, the difference value of ARR and the aldosterone before and after captopril challenge test could be associated independently with carotid artery plaque occurrence after excluding gender difference and other factors. CONCLUSION The detection rate of carotid artery plaque was high among hospitalized patients with hypertension, the difference value of ARR and the aldosterone before and after captopril challenge test could be associated independently with carotid artery plaque occurrence.
Aldosterone ; blood ; Angiotensin-Converting Enzyme Inhibitors ; pharmacology ; Captopril ; pharmacology ; Carotid Stenosis ; drug therapy ; Humans ; Hypertension ; drug therapy ; Inpatients ; Renin

Previously, we reported that high glucose enhanced cytokine-induced nitric oxide (NO) production by rat mesangial cells (MCs), and that the enhanced expression of the iNOS pathway may promote extracellular matrix accumulation by MCs. The present study was designed to examine whether the iNOS pathway is pathologically altered in experimental diabetic nephropathy, and whether therapy with angiotensin converting enzyme (ACE) inhibitor (imidapril: I) or angiotensin II type I receptor (AT1) blocker (L-158,809: L), ameliorates these changes. Male Sprague-Dawley rats were injected with diluent (control: C) or streptozotocin. At sacrifice after 4, 8 and 12 weeks, rats underwent either a 4 hour placebo or an intraperitoneal lipopolysaccharide (LPS, 2 mg/kg) challenge. Systolic blood pressure (SBP) and urinary protein excretion (UPE) increased significantly in diabetic (D) rats compared with C. The basal expression of glomerular iNOS mRNA was increased in D rats compared with that of C rats, by reverse- transcription (RT)-polymerase chain reaction (PCR), whereas there was no significant difference in the level of protein by Western blot analysis. Upon LPS stimulation, the iNOS mRNA and protein expression was significantly elevated in D rats. In D rats, this up-regulation, of LPS-stimulated iNOS expression, was equally ameliorated both by I and L in mRNA and protein levels. From immunohistochemistry (IHC), there was a negative staining for the iNOS within the glomeruli of five C rats without LPS treatment, but one of four rats, with LPS treatment, showed minimal iNOS staining in the glomeruli. In D rats, the glomerular mesangium and podocytes were positive for iNOS in each of three out of five rats with, and without, LPS treatment. In conclusion, LPS-stimulated glomerular iNOS expression was enhanced in diabetic pnephropathy, and the activation of angiotensin II may play a role in this enhancement.
Angiotensin-Converting Enzyme Inhibitors/pharmacology ; Animal ; Kidney Glomerulus/*drug effects/*enzymology ; Lipopolysaccharides/*pharmacology ; Male ; Nitric-Oxide Synthase/*metabolism ; Rats ; Rats, Sprague-Dawley ; Receptors, Angiotensin/antagonists & inhibitors

OBJECTIVETo observe the changes in the myocardial ultrastructure of diabetic rats and the effect of enalapril treatment.

METHODSMale Wistar rats were divided into 3 groups, namely the control group, diabetic group and enalapril intervention group. Diabetes was induced with peritoneal injection of streptozotocin in the latter 2 groups, and in enalapril group, the rats were treated with enalapril at the daily oral dose of 2 mg/kg for 1, 3 and 5 months after streptozotocin injection. Histological analysis of the left ventricular tissue was performed with transmission electron microscope 1, 3, and 5 months after establishment of diabetes.

RESULTSOnset of myocardial damages was observed 1 month after the development of diabetes in the rats with gradual time-dependent exacerbation. Enalapril treatment could partially reverse the myocardial destruction in the diabetic rats.

CONCLUSIONEnalapril intervention may improve the ultrastructural pathology of the myocardium in diabetic rats, which is suggestive of the action mechanisms of angiotensin-converting enzyme inhibitors in myocardium preservation.

Angiotensin-Converting Enzyme Inhibitors ; pharmacology ; Animals ; Diabetes Mellitus, Experimental ; drug therapy ; pathology ; Enalapril ; pharmacology ; Male ; Myocardium ; ultrastructure ; Rats ; Rats, Wistar ; Streptozocin

AIMTo investigate the role of tumor suppressor PTEN in cardiac hypertrophy, the expression of PTEN mRNA in left ventricle of abdominal aorta constricted-induced cardiac hypertrophic rats which treated with and without captopril was analyzed.

METHODSSD rats were divided into control group, hypertrophy group and captopril group. The expression of PTEN mRNA in left ventricle was detected by RT-PCR in different groups in 4 weeks after operation.

RESULTS(1) Compared with control group, the expression of PTEN mRNA in left ventricle of hypertrophy group was reduced. (2) Compared with hypertrophy group, the expression of PTEN mRNA in left ventricle of captopril group was upregulated, which were similar to that of control group.

CONCLUSIONPTEN maybe plays a negative regulation role in the process of cardiac hypertrophy, and the role of PTEN is closely relative with renin-angiotensin system.

Angiotensin-Converting Enzyme Inhibitors ; pharmacology ; Animals ; Captopril ; pharmacology ; Cardiomegaly ; metabolism ; pathology ; Male ; PTEN Phosphohydrolase ; metabolism ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo establish and compare three in vitro screening models of angiotensin converting enzyme inhibitors (ACEI), and provide methodological basis for screening ACEI drugs from Chinese herbal medicine.

METHODThree screening models were established using rat serum, pure angiotensin converting enzyme (ACE) and crude extract enzyme from rabbit lung as enzyme sources, respectively, with corresponding testing methods, and captopril as the positive drug.

RESULTThe IC50 of captopril was 2.30 nmol x L(-1) using rat serum as the enzyme; and 1.04 nmol x L(-1) for ACE pure enzyme; and 1.40 nmol x L(-1) for crude extract enzyme from rabbit lung.

CONCLUSIONResults from the three screening models were all in accordance with literature reports. These models can be applied to in vitro pharmaceutical screening. The selection of suitable screening model depend on the experimental situation and the inherent characters of models.

Angiotensin-Converting Enzyme Inhibitors ; analysis ; pharmacology ; Animals ; Drug Evaluation, Preclinical ; methods ; Drugs, Chinese Herbal ; analysis ; pharmacology ; Male ; Models, Animal ; Peptidyl-Dipeptidase A ; blood ; Rabbits ; Rats ; Rats, Sprague-Dawley

This study inquired about the role of tumor suppressor PTEN in the arterial remodeling of Ang II induced hypertension. The expression of PTEN of aorta was examined in the aortic-constricted hypertensive rats (hypertension group), in the aortic-constricted hypertensive rats treated with captopril(hypertension and captopril group), and in the rats having undergone sham operation (control group). At day 28 after surgery, the aortas were collected from the groups. The expression of PTEN mRNA was detected by RT-PCR. The expression and location of PTEN protein were determined by immunohistochemistry. The results showed that the expression of PTEN in aorta of the hypertension group was significantly lower than that of the hypertension and captopril group, and similarly lower than that of the control group. The intensity of PTEN-positive immunohistochemical production in aorta of the hypertension group was weaker than that of the hypertension and captopril group, and likewise, it was weaker than the control. PTEN-positive immunohistochemical production was located in VSMC of aorta. The findings indicated that the expression of PTEN is reduced in hypertensive aorta, that the reduced PTEN experession can be reversed by captopril treatment, that AngII and the increased mechanical strain may participate in regulating expression of PTEN, and that PTEN may play a role in the arterial remodeling induced by hypertension.
Angiotensin-Converting Enzyme Inhibitors ; pharmacology ; Animals ; Aorta, Abdominal ; metabolism ; Captopril ; pharmacology ; Constriction ; Genes, Tumor Suppressor ; Hypertension ; etiology ; metabolism ; Male ; PTEN Phosphohydrolase ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo determine the effects of captopril on human sperm motility in vitro.

METHODSSperm specimens were aseptically obtained by masturbation and prepared by Percoll gradient-centrifugation technique to produce a spermatozoa suspension of high motility from 12 healthy fertile men. The spermatozoa suspension were incubated with captopril at 1:9 ratio of volume at 37 degrees C in vitro, which was administrated at three different concentrations. Measurements were carried out within 5 minutes for all specimens including VAP, VSL, VCL, STR, ALH and progressive motility.

RESULTSWithin 5 minutes, three different concentrations of captopril could change the human spermatozoa motility and forward motile sperm percentage, but captopril did not decrease the other motility parameters, including VSL, VCL and VAP etc. The high concentration group could decrease the VCL more than those of the other two groups and it seemed that the velocity parameters of the middle concentration group were higher than those of the other two groups, but there were no significant difference statistically.

CONCLUSIONIt suggests that captopril can decrease the human spermatozoa motility and forward motile sperm percentage, but it can not directly affect the spermatozoa velocity in vitro.

Adult ; Angiotensin-Converting Enzyme Inhibitors ; pharmacology ; Captopril ; pharmacology ; Cells, Cultured ; Dose-Response Relationship, Drug ; Humans ; Male ; Sperm Motility ; drug effects ; Spermatozoa ; cytology ; drug effects

OBJECTIVETo compare the effects of high, middle and low doses of enalapril in preventing left ventricular remodeling (LVRM) after acute myocardial infarction (AMI) in rats, especially evaluating the efficacy of low dose enalapril.

METHODSAMI was induced by ligating the left coronary artery in 149 female SD rats. 48 hours after the procedure, the 97 surviving rats were randomized to one of the following four groups: (1) AMI controls (n = 24), (2) high-dose (10 mg x kg(-1) x d(-1), n = 25), (3) middle-dose (1 mg x kg(-1) x d(-1), n = 23), and (4) low-dose (0.1 mg x kg(-1) x d(-1), n = 25) enalapril groups. In addition, sham-operated (n = 13) and normal rats (n = 10) were randomly selected to serve as non-infarction controls. Enalapril was delivered by direct gastric gavage. After 4 weeks of therapy, hemodynamic studies were performed, then the rat hearts were fixed with 10% formalin and pathology analysis was performed. Exclusive of the dead rats and those with MI size < 35% or > 55%, complete experimental data were obtained from 67 rats, which were comprised of (1) AMI controls (n = 13), (2) high-dose enalapril (n = 13), (3) middle-dose enalapril (n = 12), (4) low-dose enalapril (n = 12), (5) sham-operated (n = 8) and (6) normal (n = 9) groups.

RESULTSThere were no significant differences among the four AMI groups in infarction size (all P > 0.05). Compared with the sham-operated group, the left ventricular (LV) end diastolic pressure (LVEDP), volume (LVV), absolute and relative weight (LVAW, LVRW) in AMI group were all significantly increased (all P < 0.001), while maximum LV pressure rising and dropping rates (+/- dp/dt) and their corrected values by LV systolic pressure (+/- dp/dt/LVSP) were all significantly reduced in the AMI control group (P < 0.01 - 0.001), indicating LVRM occurred and LV systolic and diastolic functions were impaired. Compared with the AMI group, LVEDP, LVV, LVAW and LVRW were all significantly decreased in the three enalapril groups (control P < 0.001), with the reduction of LVEDP, LVV and LVAW being more significant in high-dose than in low-dose enalapril groups (all P < 0.05), and the +/- dp/dt/LVSP were significantly increased only in the high and middle-dose enalapril groups (P < 0.01).

CONCLUSIONSHigh, middle and low doses of enalapril were all effective in preventing LVRM after AMI in the rat, with low dose enalapril being effective and high dose superior. As for LV functional improvement, only high and middle-dose enalapril were effective.

Angiotensin-Converting Enzyme Inhibitors ; administration & dosage ; pharmacology ; Animals ; Dose-Response Relationship, Drug ; Enalapril ; administration & dosage ; pharmacology ; Female ; Myocardial Infarction ; physiopathology ; Rats ; Rats, Sprague-Dawley ; Ventricular Remodeling ; drug effects