Effects of sho-saiko-to on production of prostaglandin E2 (PGE2), leukotriene B4 (LTB4) and superoxide from peripheral monocytes and polymorphonuclear cells isolated from HIV infected individuals

The effects of Sho-saiko-to (SST), a traditional Chinese medicine, on the production of PGE2 from monocytes, LTB4 and superoxide from polymorphonuclear cells (PMNC) in HIV infected individuals were studied. SST inhibited the production of PGE2 from monocytes stimulated by opsonized zymosan in all groups including the healthy control group and also inhibited the production of superoxide from PMNC after stimulation with FMLP. On the other hand, SST enhanced the production of LTB4 when PMNC were stimulated by the calcium ionophore A23187. These results suggest that SST has different effects on the production of prostanoids or superoxide from monocytes and PMNC. Furthermore, our data indicates that inhibition of PGE2 or superoxide production will lead to indirect suppression of HIV, and enhancement of LTB4 will contribute to the upregulation of the immune reaction in HIV infected individuals.

Polyethylene glycol-modified pokeweed mitogen (PWM) as a potential non-immunogenic stimulator of lymphokine-activated killer cells

Among the various plant lectins, pokeweed mitoge (PWM) is most effective in enhancing the cytotoxicity of human lymphokine-activated killer (LAK) cells. However, the use of PWM in adoptive immunotherapy has been limited due to the strong immune response against the protein of plant origin. Amino groups in PWM was modified with 2,4-bis[O-methoxypoly(ethylene glycol)]-6-chioro-s-triazine, activated PEG2, to form PEG-PWM conjugates. Its immunoreactivity towards anti-PWM antibodies was reduced by increasing the degree of modification of amino groups in PWM. PEG-PWM, in which 54% of amino groups in PWM was modified with activated PEG2, had a nearly complete reduction of immunoreactivity. Intraperitoneal administration of PEG-PWM to mice did not produce substantial levels of anti-PWM antibodies. Nevertheless, PEG-PWM retained the ability to induce the maximum levels of cytotoxicity of human LAK cells in vitro.

Tolerogenic capacity of poly(ethylene glycol) (PEG)--modified ovalbumins in relation to their immunoreactivity towards anti-ovalbumin antibody

Ovalbumin (OVA) was chemically modified with poly(ethylene glycol) (PEG) derivatives: activated PEG2, 2,4-bis[O-methoxypoly(ethylene glycol)]-6-chloro-s-triazine and activated PM13, copolymer of poly(oxyethylene) allyl methyl diether and maleic anhydride. Pretreatment of BALB/c mice with PEG2- or PM13-OVA suppressed the production of both IgG- and IgE-class anti-OVA antibodies induced by subsequent immunizations with unmodified OVA. PEG2-OVA had higher potency to suppress OVA-specific immune response than PM13-OVA. Although extensive modification (62%) of amino groups in the OVA molecule with activated PEG2 was required to diminish most of its immunoreactivity towards anti-OVA antibodies, only a low degree of modification (27%) was sufficient to induce tolerogenicity to OVA. Thus, the loss of immunoreactivity of PEG2-OVA was not prerequisite for its tolerogenic capacity. Moreover, the use of completely denatured PEG2-OVA immunogen lead to the loss of its ability to induce immune tolerance to native OVA. These observations are discussed in relation to the regulatory mechanism of immune response.

Mapping of angiotensin II receptor subtypes in peripheral tissues of spontaneously hypertensive rats by in vitro autoradiography

1. The regulation of angiotensin II (AII) receptor subtypes was studied in peripheral tissues of 20 week old male spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar-Kyoto (WKY) rats. 2. AII receptor binding was determined by a quantitative in vitro autoradiography using [125I]-[Sar1,Ile8]AII as a ligand on the kidney, adrenal gland, thoracic aorta and heart. CV-11974, a specific AT1 receptor antagonist, and CGP42112B, a specific AT2 antagonist, were used in competition with [125I]-[Sar1,Ile8]AII to differentiate AT1 and AT2 receptor binding. 3. The relative abundance of each subtype was very similar between SHR and WKY rats. In both strains of rats, the adrenal cortex contained predominantly AT1 receptors, while AT2 receptors predominated in the adrenal medulla. The kidney contained exclusively AT1 receptors over glomeruli, proximal tubules and outer medulla. AT1 receptors were predominant in the thoracic aorta and heart. 4. As for relative receptor density, important differences were observed between SHR and WKY rats. In SHR, the adrenal cortex, outer medulla of the kidney, and heart displayed higher AT1 receptor density than WKY rats. 5. These results indicate that the expression of AT1 receptors is differently regulated in some important targets of AII in SHR, and suggest that the altered regulation of AT1 receptor presented in this study should be relevant to the pathophysiological features of SHR.

Inhibition of Df-protease--induced kinin release by synthetic inhibitors

A protease (Df-protease) from house dust mite (D. farinae) is closely associated with mite-induced allergy: Df-protease has a similar substrate specificity to blood coagulation factor XIIa and catalyzes the activation of kallikrein-kinin system in human plasma. With the purpose of prevention of kinin-formation in plasma by Df-protease, inhibition of Df-protease with synthetic inhibitors was tested in vivo and in vitro. Among the inhibitors, including amidine and guanidine derivatives, N-allyl-N-[4-(4-amidinophenoxycarbonyl)-alpha-methylcinnamoyl++ +]glycine ethyl ester mesylate was the most effective to inhibit Df-protease with Ki = 9 x 10(-9) M and also to prevent kinin-release from Df-protease in human plasma. Enhancement of vascular permeability in guinea pigs caused by kinin-release was stoichiometrically suppressed by the inhibitor.

"Plasmatic imbibition" in the rabbit flow-through venous flap, using horseradish peroxidase and fluorescein

In the present study, the phenomenon of "plasmatic imbibition" was investigated histologically in a rabbit flow-through venous flap model, using horseradish peroxidase and fluorescein. Horseradish peroxidase introduced between the flap and the recipient bed, produced brown staining of the entire contact surface 10 min postoperatively. At 30 min, erythrocytes in the flow-through vein stained red. The flap and the erythrocytes became more intensely stained over time. When horseradish peroxidase was introduced from a central artery after a Silastic sheet had been inserted between the flap and recipient bed, the flap color became a soft brown and the erythrocytes of the flow-through vein stained red 10 min postoperatively. In the experimental groups subjected to fluorescein, introduced between the graft (or flap) and the recipient bed, fluorescence was seen 10 min postoperatively, except in the flow-through vein. At 30 and 120 min, the whole graft (or flap) showed fluorescence. Fluorescein was introduced into the femoral vein after flap elevation, or a Silastic sheet was inserted between the flap and the recipient bed. At 10 min, these groups showed a weak fluorescence only in the flow-through vein; subsequently, at 120 min, the flow-through vein and its surrounding tissue showed fluorescence, but the flap showed none. Plasmatic imbibition was proved to be acting in the flow-through vein, and it is considered as important a phenomenon in flap survival as venous flow itself.

Angiotensin II type I receptor antagonist inhibits the gene expression of transforming growth factor-beta 1 and extracellular matrix in cardiac and vascular tissues of hypertensive rats

TCV-116 [(+/-)-(cyclohexyloxycarbony-loxy)ethyl2-ethoxy-1-[[2' -(1H- tetrazol-5-yl)biphenyl-4-yl]methyl]-1H-benzimidazole-7-carboxylate ], a nonpeptide selective angiotensin II type I receptor (AT1 receptor) antagonist, at the dose of 0.1, 1 or 10 mg kg-1 day-1, was orally given to 22-week-old stroke-prone spontaneously hypertensive rats (SHRSP) for 10 weeks (from the age of 22-32 weeks) to examine the effects on gene expression of transforming growth factor-beta 1 (TGF-beta 1) and extracellular matrix proteins in the heart and blood vessels. Tissue messenger RNA (mRNA) was measured by northern blot analysis, with a specific complementary DNA probe. In the heart, left ventricular mRNA levels for fibronectin; types I, III and IV collagen; and laminin were significantly higher in SHRSP than control Wistar-Kyoto rats. In the mesenteric artery and aorta of SHRSP, TGF-beta 1 mRNA and the mentioned extracellular matrix protein mRNAs were increased compared with Wistar-Kyoto rats. Thus, the expression of various genes was up-regulated in cardiovascular tissues of SHRSP. Treatment of SHRSP with TCV-116 suppressed the gene expression of the mentioned extracellular matrix proteins and TGF-beta 1 in both heart and blood vessels in a dose-dependent fashion. Furthermore, TCV-116 regressed cardiac hypertrophy and lessened the medial hypertrophy of the aorta in SHRSP. These results show that angiotensin AT1 receptor antagonist in vivo can inhibit the gene expression of TGF-beta 1 and extracellular matrix proteins in hypertensive cardiovascular tissues. These effects may contribute to the beneficial effects of AT1 receptor antagonist on hypertensive cardiac hypertrophy and vascular thickening.

Biomedical and biotechnological applications of PEG- and PM-modified proteins

Chemical modification of proteins and other bioactive molecules with polyethylene glycol (PEG) or its derivatives (PM) can be used to tailor molecular properties to particular applications, eliminating disadvantageous properties or conferring new molecular functions. Complexes of therapeutic proteins and PEG or PM show reduced immunoreactivity, prolonged clearance times and improved biostability. Modification with PEG can also increase the solubility and activity of enzymes in organic solvents, thus extending their potential for application in organic syntheses and biotransformation processes.

Effects of delapril on stroke, kidney dysfunction and cardiac hypertrophy in stroke-prone spontaneously hypertensive rats

This study was performed to investigate the beneficial effects of prolonged treatment with an angiotensin converting enzyme (ACE) inhibitor, delapril, on the appearance of symptoms of hypertensive cardiovascular disease in stroke-prone spontaneously hypertensive rats (SHRSP). Cardiovascular disease symptoms: stroke, kidney dysfunction and cardiac hypertrophy, were evaluated by monitoring the incidence of stroke signs, urinary excretion of protein and the heart weight, respectively. The SHRSP that were kept under salt-loaded conditions (1% NaCl drinking solution) from six weeks of age developed severe hypertension, showed an increased incidence of stroke signs and increased urinary excretion of protein. Long-term treatment with delapril (10mg/kg/day, p.o. for four weeks) decreased the blood pressure and completely inhibited the incidence of stroke signs and the increase in urinary excretion of protein. In SHRSP that were kept under normal conditions (without 1% NaCl drinking solution), long term treatment with delapril at the same dose decreased the heart weight and, after five weeks of treatment, left ventricular weight was decreased significantly and the wall/lumen ratio of small coronary arterioles and the thickness of the left ventricular wall were decreased slightly. These results indicate that delapril can prevent the development of symptoms of hypertensive cardiovascular diseases: stroke, kidney dysfunction and cardiac hypertrophy, with antihypertensive activity in SHRSP.

Role of angiotensin II in cerebrovascular and renal damage in deoxycorticosterone acetate-salt hypertensive rats

OBJECTIVE AND DESIGN

To study the effects of blockade of the renin-angiotensin system on the development of hypertension and end-organ damage in hyporeninaemic deoxycorticosterone acetate (DOCA)-salt hypertensive rats, using an angiotensin II (Ang II) receptor antagonist (TCV-116) or an angiotensin converting enzyme (ACE) inhibitor (enalapril).

METHODS

DOCA-salt hypertensive rats were produced by uninephrectomy, implantation with DOCA pellets and 1% NaCl loading. TCV-116 (0.1 or 1 mg/kg) or enalapril (10 mg/kg) was given orally once a day from 3 to 6 weeks after the operation. Body weight, blood pressure, plasma renin and creatinine, urinary protein and blood urea nitrogen were measured. After 3 weeks' treatment, oedema and omega 3-subtype benzodiazepine receptor binding in the brain were measured.

RESULTS

Three weeks after the operation the blood pressure in the DOCA-salt hypertensive rats was approximately 200 mmHg, and the plasma renin concentration was lower than in sham-operated rats. However, after a further 3 weeks the renin concentration was slightly above the normal level, and this increase was accompanied by a decrease in body weight and increases in blood urea nitrogen, plasma creatinine, urinary protein and omega 3-subtype benzodiazepine receptor binding in the cerebral cortex, and by brain oedema. Treatment with TCV-116 or enalapril prevented renal damage and decrease in body weight with little effect on blood pressure. Enalapril prevented brain oedema and the increase in benzodiazepine binding in the brain cortex, and 1 mg/kg TCV-116 prevented them markedly.

CONCLUSIONS

Although the hypertension in DOCA-salt hypertensive rats is independent of the renin-angiotensin system, the degree of cerebral and renal damage is associated with the activity of the renin-angiotensin system and has little relationship with the blood pressure level.

Contribution of renal angiotensin II type I receptor to gene expressions in hypertension-induced renal injury

Recent evidence indicates that transforming growth factor-beta 1 (TGF-beta 1) plays an important role in renal fibrosis via stimulation of extracellular matrix synthesis. The present study was undertaken to investigate the role of angiotensin II type I receptor (AT1 receptor) in hypertension-induced renal injury. Twenty-two-week-old stroke-prone spontaneously hypertensive rats (SHRSP), which had established hypertension and moderate renal damage, were orally given TCV-116, a selective non-peptide AT1 receptor antagonist (0.1, 1 or 10 mg/kg/day), enalapril (10 mg/kg/day) or vehicle once a day for 10 weeks. At the end point of the treatment, we examined renal function, the gene expressions of TGF-beta 1 and extracellular matrix components in the interstitium [collagen types I (COI) and III (COIII), fibronectin (FN)] and the basement membrane (COIV and laminin), and renal microscopic morphology in rats aged 32 weeks. In vehicle-treated 32 week-old SHRSP with renal dysfunction and nephrosclerosis, renal mRNA levels for TGF-beta 1, COI, COIII, FN, COIV were all several-fold higher than in WKY. Thus, renal TGF-beta 1 gene expression was enhanced in SHRSP, which may contribute to the increased renal expressions of COI, COIII, FN, COIV in SHRSP. Treatment with TCV-116 (0.1 mg/kg/day) in SHRSP, in spite of no reduction of blood pressure, decreased renal mRNA levels for TGF-beta 1, COI, COIII, FN, COIV, being accompanied by the significant decrease in urinary protein and albumin excretion, blood urea nitrogen and plasma creatinine. Treatment with TCV-116 (10 mg/kg/day) in SHRSP decreased mRNAs for TGF-beta 1, COI, COIII, FN and COIV to almost the same levels as WKY, being associated with normalization of urinary protein and albumin excretion and the prevention of nephrosclerosis, as judged by microscopic histological observations. On the other hand, the effects of enalapril (10 mg/kg/day) on the above mentioned mRNA levels, renal function and renal morphology were weaker than those of TCV-116 (10 mg/kg/day) and were as much as TCV-116 (1 mg/kg/day). These results suggest that independently of hypotensive action, AT1 receptor antagonist has a potent renal protective effect by inhibiting the gene expression of renal TGF-beta 1 and extracellular matrix components.

[Clinical evaluation of controlled hypotensive anesthesia with MR7S1]

Efficacy, safety and the optimal dose of MR7S1, an injectable preparation of sodium nitroprusside, were studied in 37 patients (ASA class I and II) under nitrous oxide-oxygen-enflurane anesthesia. MR7S1 was administered by intravenous infusion. The dose of MR7S1 was increased gradually starting from 0.25 micrograms.kg-1.min-1 to the dose which could achieve the target value of systolic blood pressure (80-100 mmHg). Thereafter this dose level was maintained. During the period in which the dose was increased, the blood pressure was reduced in proportion to the rate of administration. With the rate of administration of 1.0 to 3.0 micrograms.kg-1.min-1, a significant decrease in systolic blood pressure (SBP) was observed compared with the pretreatment level of SBP. During the maintenance period, the SBP was maintained around 80 to 100 mmHg at a rate of administration of 0.25 to 3.5 micrograms.kg-1.min-1. Two out of 37 patients showed a slight decrease in PaO2, but these values returned to normal without any treatment. These findings suggest that MR7S1 is a useful agent to control blood pressure for the hypotensive anesthesia.

Short-term effects of angiotensin II blockade on renal blood flow and sympathetic activity in awake rats

To investigate the effects of an angiotensin II type 1 receptor antagonist (CV-11974) on renal blood flow and renal sympathetic nerve activity compared with a calcium antagonist (nicardipine), we measured both parameters in conscious spontaneously hypertensive rats aged 13 to 15 weeks. One to 2 days after surgery, CV-11974 (n = 9) and nicardipine (n = 8) were intravenously administered to decrease arterial pressure in a similar time course and degree of hypotension. CV-11974 increased renal blood flow by 23 +/- 4% at the maximal fall in mean arterial pressure (-32 +/- 1 mm Hg), and renal nerve activity increased by 70 +/- 7%. The maximal increase in renal blood flow (+27 +/- 4%) was observed when mean pressure was reduced by approximately 20 mm Hg. The maximal reduction of renal vascular resistance (-33 +/- 3%) correlated significantly with pretreatment levels of plasma renin concentration (r = -.792). In contrast, nicardipine produced a progressive reduction of renal blood flow and marked increases in heart rate and renal nerve activity. Increases in heart rate and nerve activity were greater than those with CV-11974 treatment (P < .001). At the maximal fall in mean pressure (-32 +/- 1 mm Hg), renal blood flow decreased by 23 +/- 4%, which was significantly correlated with percent changes in renal nerve activity (+150 +/- 11%, r = -.744). Renal denervation in another set of rats (n = 6) improved renal blood flow and renal vascular resistance responses to nicardipine.(ABSTRACT TRUNCATED AT 250 WORDS)

[Nonpeptide angiotensin II-receptor antagonists]

The renin-angiotensin system (RAS) is known to play a very important role in cardiovascular diseases. The present state of the research on orally active nonpeptide angiotensin II (A II)-receptor antagonists and their pharmacological characterization will be reviewed. In the late 1970s, the first nonpeptide A II-receptor antagonists were discovered among some derivatives of imidazoleacetic acid, and this was followed by the development of losartan in 1989. TCV-116, synthesized in our laboratories, is a prodrug that is converted in vivo to the active form CV-11974. TCV-116 and CV-11974 were demonstrated to be effective antagonists for many A II-induced cardiovascular actions and are effective antihypertensive agents in several animal models of hypertension. TCV-116 also demonstrated secondary benefits in treating congestive heart failure (CHF), preventing stroke, delaying the progression of renal disease and preventing the intimal thickening of vascular injury in animal models. Clinical studies confirmed the efficacy of TCV-116 in the treatment of essential hypertension. The utility of A II antagonist may extend beyond that of hypertension and CHF, as suggested by the potential usefulness of ACE inhibitors in the treatment or prevention of many other cardiovascular diseases. The A II antagonists will help to determine the role of the RAS in the physiologic regulation and in the pathophysiology of various cardiovascular diseases.

Role of angiotensin II in renal injury of deoxycorticosterone acetate-salt hypertensive rats

To investigate the role of angiotensin II (Ang II) in hypertension-induced tissue injury, we gave TCV-116 (1 mg/kg per day PO), a nonpeptide Ang II type I receptor antagonist, or enalapril (10 mg/kg per day PO) to deoxycorticosterone acetate (DOCA)-salt hypertensive rats for 3 weeks and examined the effects on tissue mRNA levels for transforming growth factor-beta 1 (TGF-beta 1) and extracellular matrix components. Tissue mRNA levels were measured by Northern blot analysis. Renal mRNA levels for TGF-beta 1; types I, III, and IV collagen; and fibronectin in DOCA-salt hypertensive rats were increased by severalfold (P < .01) compared with sham-operated rats. In the aorta of DOCA-salt hypertensive rats, TGF-beta 1 and fibronectin mRNA levels were increased, but types I, III, and IV collagen mRNAs did not increase. In the heart, increased mRNA was found only for fibronectin. Thus, these gene expressions are regulated in a tissue-specific manner. TCV-116 or enalapril did not lower blood pressure in DOCA-salt hypertensive rats. However, the increase in renal mRNAs for TGF-beta 1 and extracellular matrix components in DOCA-salt hypertensive rats was significantly inhibited by treatment with TCV-116 or enalapril, which was associated with a significant decrease in urinary protein and albumin excretions and histological improvement of renal lesions. In contrast, in the aorta and heart these gene expressions were not affected by TCV-116 or enalapril. Thus, local Ang II may contribute to renal injury of DOCA-salt hypertension by stimulating the gene expression of TGF-beta 1 and extracellular matrix components.

Anti-hypertensive effect of oral controlled-release microspheres containing an ACE inhibitor (delapril hydrochloride) in rats

An oral controlled-release drug delivery system based on microspheres of polyglycerol esters of fatty acids (PGEFs), was applied to an anti-hypertensive, delapril hydrochloride. The in-vitro release profile was controlled by selecting a PGEF with an appropriate hydrophilic-lipophilic balance value for the matrix. The microspheres from which 80% of the drug was released in 6 h were orally administered to rats. The plasma concentration of the active metabolite was sustained after administration of the microspheres in comparison with administration of a solution. The in-vivo release profile was in good agreement with the in-vitro release profile. When the microspheres were administered, the pharmacological effect of delapril hydrochloride on the angiotensin I-induced pressor response was also sustained showing consistency with the plasma concentration-time curve.

Stabilization of L-asparaginase modified with comb-shaped poly(ethylene glycol) derivatives, in vivo and in vitro

L-Asparaginase from Escherichia coli was coupled with two types of comb-shaped copolymer of poly-(ethylene glycol) derivative and maleic anhydride (activated PM), having molecular weights of 13,000 and 100,000 (activated PM13 and PM100, respectively) with multivalent reaction sites. After single intravenous injections of PM100-asparaginase and nonmodified asparaginase into rats, the enzymic activity of PM100-asparaginase in serum was well retained for at least 11 days, and the serum L-asparagine concentration remained undetectable for 27 days. The half-lives of PM100-asparaginase and nonmodified asparaginase were 50 and 1.5 h, respectively. Stabilization of L-asparaginase toward heat, urea, and acidity was caused by modifying the enzyme with activated PM13 and PM100. Especially, PM100-asparaginase retained high enzymic activity toward heat and urea, compared with PM13-asparaginase. It was suggested that these modifiers with a comb-shaped form and with multivalent reactive sites cover the whole surface of the asparaginase molecule and stabilize its conformation possibly through multiple covalent bindings and through various noncovalent interactions.

Novel subtype of human angiotensin II type 1 receptor: cDNA cloning and expression

Angiotensin II (AII) plays a major role in regulation of cardiovascular function and fluid homeostasis through the action of an AII type 1 receptor (AT1R). The cDNA encoding a novel subtype of human AT1R (AT1bR) was cloned from a human placental cDNA library. The full-length cDNA clone (1563 bp) encoded a polypeptide that consists of 359 amino acid (aa) residues with 97.2% aa identity to the human AT1aR. All the aa replacements between two human AT1Rs reside within the C-terminal half region of AT1R molecule. The 2.4-knt AT1bR mRNA is expressed in the lung, placenta and liver, and differs from AT1aR mRNA in its tissue distribution. The AT1bR expressed in COS-7 cells is pharmacologically distinct from the human AT1aR.

Synthesis and angiotensin converting enzyme-inhibitory activity of N-[(1S)-1-carboxy-5-(4-piperidyl)pentyl]-L-alanine derivatives

As part of a search for potent and long-lasting angiotensin converting enzyme (ACE) inhibitors, various types of N-[(1S)-1-carboxy-5-(4-piperidyl)pentyl]-L-alanine derivatives (7a, 8-11) were prepared. The key synthetic intermediate, N-[(1S)-5-(1-benzyloxycarbonyl-4-piperidyl)-1- ethoxycarbonylpentyl]-L-alanine (17a), was synthesized by asymmetric reduction of the alpha-oxoester (13) with Lactobacillus paracasei subsp. paracasei followed by a substitution reaction with tert-butyl L-alaninate (15) and subsequent treatment with hydrogen chloride. Compounds 7a and 8-11 showed potent and long-lasting ACE-inhibitory activity in rats.

Antihypertensive effects of a highly potent and long-acting angiotensin II subtype-1 receptor antagonist, (+-)-1-(cyclohexyloxycarbonyloxy)ethyl 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl]-1H- benzimidazole-7-carboxylate (TCV-116), in various hypertensive rats

The antihypertensive effects of (+-)-(cyclohexyloxycarbonyloxy)ethyl2-ethoxy-1-[[2'-(1H- tetrazol-5- yl)biphenyl-4-yl]methyl]-1-H-benzimidazole-7-carboxylate (TCV-116), an angiotensin II (AII) subtype-1 receptor antagonist, were studied in various hypertensive and normotensive rats, using 2-n-butyl-4-chloro-5-hydroxymethyl-1-[(2'-(1H-tetrazol-5-yl)bip hen yl-4- yl)methyl]-imidazole, potassium salt (losartan) as a reference compound. TCV-116 is a prodrug, which is converted in vivo to the active component, 2-ethoxy-1-[[2'-(1H-tetrazol-5-yl)biphenyl-4-yl)]methyl]-1H- benzimidazole-7-carboxylic acid (CV-11974). In spontaneously hypertensive rats (SHR) p.o. TCV-116 (0.1 mg/kg) demonstrated a sustained antihypertensive effect that lasted for more than 10 hr and the dose that reduced the blood pressure by an average of 25 mm Hg for 24 hr (ED25), was 0.68 mg/kg. Intravenous CV-11974 reduced the blood pressure with an ED25 of 0.0027 mg/kg. Repeated p.o. administration of TCV-116 (1 mg/kg) to SHR once daily for 2 weeks reduced the blood pressure by 30 to 50 mm Hg over 24 hr without any heart rate changes. The antihypertensive effects of TCV-116 correlated well with the inhibition of angiotensin II-induced contractile responses of aortic strips prepared ex vivo after p.o. administration of TCV-116. Oral TCV-116 had a sustained antihypertensive effect with ED25 of 0.03 and 0.23 mg/kg in two-kidney, one-clip and one-kidney, one-clip hypertensive rats, respectively, and was much more potent in SHR and renal-hypertensive rats than losartan.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcoholysis of epsilon-decalactone with polyethylene glycol-modified lipase in 1,1,1-trichloroethane

Lipase from Pseudomonas cepacia was modified with 2,4-bis[O-methoxypoly(ethylene glycol)]-6-chloro-s-triazine, activated PEG2, to form PEG-lipase. The PEG-lipase is soluble and active in organic solvents. It catalyzes alcoholysis of racemic epsilon-decalactone with ethanol in 1,1,1-trichloroethane to form (R)-hydroxydecanoic acid ethyl ester. No alcoholysis of (S)-decalactone takes place. These results were discussed in relation to carbon number of n-alcohol, optimum temperature and comparison with modified and non-modified lipases.

Effect of an angiotensin II receptor antagonist, CV-11974, and its prodrug, TCV-116, on production of aldosterone

In dispersed rabbit adrenocortical glomerulosa cells, a non-peptide angiotensin II (AT1) receptor antagonist, CV-11974 (10(-10)-10(-5) M), competitively inhibited angiotensin II- or angiotensin III-stimulated aldosterone production, whereas PD123177, an angiotensin AT2 receptor antagonist, did not. CV-11974 inhibited aldosterone production induced by 4 mM K+ but not by 12 mM K+. CV-11974 had no effect on adrenocorticotropic hormone-stimulated aldosterone or corticosterone production, but inhibited angiotensin II-stimulated corticosterone production. In the rat, TCV-116, the prodrug of CV-11974, (0.1 and 1 mg/kg, p.o.) markedly reduced the elevation of both plasma aldosterone concentration and blood pressure induced by i.v. infusion of angiotensin II. In spontaneously hypertensive rats, TCV-116 at daily p.o. doses of 0.1, 1 and 10 mg/kg for 2 weeks caused a dose-dependent reduction of blood pressure and plasma aldosterone concentration without affecting plasma corticosterone. Thus, TCV-116 inhibited the induction of aldosterone production by not only exogenous but also endogenous angiotensin II.