Journal of pharmacobio-dynamics最新文献

Antihypertensive effects of FRC-8653, a new 1,4-dihydropyridine derivative, and its combined effects with an angiotensin converting enzyme (ACE) inhibitor, a diuretic, and a beta-adrenergic blocking agent were examined in conscious spontaneously hypertensive rats (SHR). When administered intravenously to SHR (10, 30 micrograms/kg), FRC-8653 lowered blood pressure more slowly and sustained it longer than nifedipine and nicardipine. Consecutive once-daily administrations of FRC-8653 to SHR (3 mg/kg, p.o.) produced a stable reduction of blood pressure throughout the experimental period of 29 d. When blood pressure was continuously measured for 24 h in conscious unrestricted SHR, orally administered FRC-8653 produced a long-lasting reduction in blood pressure. When concomitantly used with atenolol (30 mg/kg, p.o.), the antihypertensive effect of FRC-8653 was augmented in both potency and duration. However, simultaneous administration of captopril (30 mg/kg, p.o.) or hydrochlorothiazide (2.5 mg/kg, p.o.) did not modify the antihypertensive effect of FRC-8653.

Effects of 1-[(2-Thiazolin-2-yl)amino]acetyl-4-(1,3-dithiol 2-ylidene)-2,3,4,5-tetrahydro-1H-1-benzazepin-3,5-dione hydrochloride (KF-14363), a hepatoprotective compound, on liver regeneration, liver nucleic acid levels, mitochondrial respiration activity and hepatic energy metabolism after partial hepatectomy (OPE) in rats were studied. The liver regeneration rate was significantly increased in rats administered 100 mg/kg of KF-14363 for 6 d as compared with the control group administered vehicle. The serum glucose level in rats administered 100 mg/kg of KF-14363 measured 3 h after OPE (OPE 3 h) was significantly higher than that in rats administered vehicle (group A) and the serum insulin level in the KF-14363 group was more than double that of group A. KF-14363 also significantly increased liver nucleic acid levels in OPE rats. In mitochondrial function experiments, KF-14363 (100 mg/kg) was orally administered 2 h after OPE. Three hours after OPE (1 h after KF-14363 administration), state 3 respiration was significantly higher in the OPE 3 h + KF-14363 group than in the OPE 3 h + water group. The adenosine diphosphate/oxygen (ADP/O) ratio was also significantly higher in the OPE 22 h (22 h after OPE) + KF-14363 group than in the OPE 22 h + water group. On hepatic energy metabolism, KF-14363 increased adenosine diphosphate and triphosphate levels. Total adenine nucleotide level in the OPE 3 h + KF-14363 group was significantly higher than that in the OPE 3 h + water group. Adenylate energy charge (AEC) was slightly decreased in the OPE 3 h + water group and significantly decreased in the OPE 22 h + water group than in the corresponding sham group.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of (S)-1[6-amino-2[[hydrozy(4- phenylbutyl)phosphinyl]oxy]-1-oxohexyl]-L-proline (SQ 29 852), a phosphorus-containing novel angiotensin converting enzyme inhibitor (ACEI), which is synthesized aiming an ACEI with long-lasting activity and with few side effects, were studied using anesthetized dogs. SQ 29 852 was equipotent with captopril to modify blood pressure response of the animals to angiotensin I (Ang I) and bradykinin (Bdk). An intravenous infusion of SQ 29 852 at 0.1 mg/kg/min for 30 min caused a remarkable hypotension without reflex tachycardia in open-chest dogs. In these animals cardiac contractility (dP/dtmax of left ventricular pressure) appeared to be reduced by SQ 29 852 without any changes in right atrial pressure (RAP), left ventricular end-diastolic pressure (LVEDP) and aortic blood flow (AoF, cardiac output). In sodium-restricted dogs, the hypotension and renal vasodilation by SQ 29 852 (at 0.01, 0.1, and 1 mg/kg, i.v.) were slightly pronounced compared with animals fed with normal diet. It is demonstrated from these results that SQ 29 852 has comparable potency with captopril to inhibit angiotensin converting enzyme (ACE) activity and as common a pharmacological profile as ACEI. SQ 29 852 may be a favorable antihypertensive agent, if its long-lasting activity and few side effects are confirmed.

Glycine conjugation of a series of substituted benzoic acids was investigated in the mouse liver and kidney mitochondria. Correlations between the structure of 24 substituted benzoic acids and glycine conjugation were obtained. The extent of glycine conjugation of a series of substituted benzoic acids in liver mitochondria was different from that in kidney mitochondria. Glycine conjugation increased with greater lipid solubility in the mouse liver and kidney. The steric effect of the substituent had a far greater influence over the glycine conjugation in kidney, while the size of the substituent played a small role in the pattern of conjugation in liver. The formation of the glycine conjugate in liver was also dependent on the substituent electronegativity.

In order to elucidate the interaction between cyproheptadine (CPH) and tipepidine (TP), the disposition of CPH and its metabolites from plasma and the hepatic drug metabolizing enzyme activities in rats dosed singly or repeatedly were investigated. The elimination of CPH and its metabolites, desmethylCPH (DMCPH) and DMCPH-epoxide (DMCPHEPO), from plasma after a single intravenous (i.v.) administration of both CPH and TP was not significantly altered compared with that after CPH alone, although the i.v. administration of DMCPH and TP enhanced the plasma levels of DMCPHEPO. The elimination of TP from plasma was not affected by the coadministration with CPH. The single oral administration of both CPH and TP (50 mg/kg) significantly enhanced the plasma levels of CPH and DMCPH compared with those after CPH alone, consequently resulting in their delayed elimination. However, the coadministration with TP at a low dose (5 mg/kg) hardly affected the plasma decay of CPH and its metabolites. The repeated dosing of them for 7 d obscured the interactive effect. The hepatic drug-metabolizing enzyme activities, cytochrome P-450 and aminopyrine demethylase activity, were greatly increased after the repeated administration of CPH, especially showing much more increased activities after the coadministration with TP. These results suggest that the competition of hepatic oxidative metabolism between CPH or its metabolites and TP based on the depletion of the enzymes might largely be involved in the drug interaction on a single dosing of them and that the repeated dosing of them would dissolve the depletion due to their strongly inductive effect.

Plasters containing methyl salicylate with and without l-menthol and dl-camphor were prepared and topically applied on hairless mouse skin to investigate the effects of l-menthol and dl-camphor on the skin penetration and hydrolysis of methyl salicylate in the skin. The in vitro hydrolysis of methyl salicylate was also investigated using the skin homogenate. It was found that l-menthol with dl-camphor enhanced the skin penetration of methyl salicylate, and they inhibited both the in vivo and in vitro hydrolysis of methyl salicylate to salicylic acid.

The present study examined the effects of (1-[(2-thiazolin-2-yl)amino]-acetyl-4-(1,3-dithiol-2-ylidene)-2,3, 4,5- tetrahydro-1H-1-benzazepin-3,5-dione hydrochloride (KF-14363) on liver fibrosis in rats with chronic liver injury induced by carbon tetrachloride (CCl4). Liver injury in male rats was induced by repeated administration of CCl4 at 0.5 ml/kg twice a week. The progression of liver fibrosis was checked in the 4th, 6th, 8th and 10th weeks using the relative amount of hepatic 4-hydroxy proline (4-hyp) to total proteine as an index of hepatic collagen. The relative amount of hepatic 4-hyp in these rats exceeded significantly that in rats not administered CCl4 by the 4th week. This progressed in proportion to the duration of CCl4 administration. In groups concurrently administered KF-14363 at 30 and 100 mg/kg/d from the 5th or 8th week of the CCl4 administration, the relative amount of hepatic 4-hyp was found to be lower in the 10th week than at the start of the KF-14363 administration. The inhibition of liver fibrosis was also observed histopathologically. The concurrently co-administration with CCl4 or KF-14363 at 30 and 100 mg/kg for 2 or 5 weeks inhibited the increases in serum transaminases and alkaline phosphatase induced by CCl4. The results show that KF-14363 inhibits liver fibrosis in a dose dependent fashion in rats with progressive liver injury.

Plasma levels of haloperidol decanoate and haloperidol after intramuscular administration of haloperidol decanoate in rats showed good fits with a multi-compartment model which was constituted by combination of 2-compartment models for the disposition of haloperidol and for its ester decanoate through the process of hydrolysis of the ester. Calculated parameters indicated that most of intramuscularly administered haloperidol decanoate is absorbed in blood after hydrolysis to haloperidol and the absorption is rate-limiting. Regional lymph node levels suggested that the intramuscularly administered ester was absorbed via the lymphatic system where the hydrolysis to haloperidol probably occurred. Thus, slow entrance and hydrolysis of haloperidol decanoate in the lymphatic system was considered to be the cause of sustained plasma levels of the active principle after intramuscular administration of haloperidol decanoate.