Hormonal effects of Z-350, possessing steroid 5alpha-reductase inhibitory and alpha1-adrenoceptor antagonistic actions, in the rat.

We examined the hormonal effects of Z-350, (S)-4-[3-(4-[1-(4-methylphenyl)-3-[4-(2-methoxyphenyl)piperazine-1-yl]propoxy]benzoyl)indole-1-yl]butyric acid hydrochloride, which has both alpha1-adrenoceptor blocking activity and steroid 5alpha-reductase inhibitory activity, in male and female rats. Z-350 administered orally for 14 days at a dose of 30 mg/kg to normal male rats significantly reduced the weight of the prostate and seminal vesicles without affecting the weight of the testis, epididymis, adrenals, kidney or liver. Prostatic levels of dihydrotestosterone decreased dose-dependently, with a slight increase in the level of testosterone at a Z-350 dose of 100 mg/kg. We observed no effects on the weight of the prostate in castrated rats or on the weight of the uterus in normal or 17beta-estradiol-treated female rats. These results suggest that Z-350 inhibits prostatic growth via inhibition of steroid 5-reductase without other hormonal effects.

[Effect of liver hydrolysate on hepatic proliferation in regenerating rat liver].

The effect of liver hydrolysate (LH) derived from bovine liver on rat liver regeneration after partial hepatectomy (PH) were investigated. Oral administration of LH increased rat liver weight dose-dependently at 24 h after PH. Hepatic ornithine decarboxylase (ODC) activity and proliferating cell nuclear antigen (PCNA) labeling index were measured in regenerating rat liver as markers of cell proliferation. ODC activities at 4 and 24 h after PH were significantly increased by LH administration. PCNA labeling index at 24 h after PH were also increased by LH administration. These results suggest that LH stimulates liver regeneration in partially hepatectomized rats.

Z-350, a new chimera compound possessing alpha1-adrenoceptor antagonistic and steroid 5alpha-reductase inhibitory actions.

The effects of Z-350, (S)-4-[3-(4-{1-(4-methyl-phenyl)-3-[4-(2-methoxyphenyl)piperazine-1-yl]propoxy} benzoyl)indole-1-yl]butyric acid hydrochloride, a newly synthesized compound possessing alpha-adrenoceptor antagonistic and steroid 5alpha-reductase inhibitory actions, were studied in vitro. In functional experiments, Z-350 shifted the concentration/response curve for the phenylephrine-induced contraction of rabbit prostate, urethra and aorta to the right with pA2 values of 8.04, 7.57 and 7.13, respectively. The binding affinity of Z-350 for alpha1-adrenoceptors in rabbit prostate, urethra and aorta were estimated by the displacement of [3H]prazosin. The pKi values for this action of Z-350 were 7.53, 7.95 and 7.62 for the prostate, urethra and aorta, respectively. alpha1-Adrenoceptor subtype selectivities were studied in the submaxillary gland (r(1A) and liver (alpha1B) of rat. Z-350 inhibited the specific binding of [3H]prazosin to alpha1A and (alpha1B-adrenoceptors with pKi values of 7.82 and 7.29, respectively. Z-350 inhibited rat prostatic steroid 5alpha-reductase non-competitively with a pIC50 of 8.42. These results indicate that Z-350 is a alpha1-adrenoceptor antagonist and is a steroid 5alpha-reductase inhibitor. It is expected that Z-350 will be a candidate drug for the treatment of benign prostatic hyperplasia.

Z-350, a novel compound with alpha 1-adrenoceptor antagonistic and steroid 5 alpha-reductase inhibitory actions: pharmacological properties in vivo.

The alpha(1)-adrenoceptor-antagonistic and steroid 5alpha-reductase-inhibitory actions of Z-350 [(S)-4-{3-{4-{1-(4-methylphenyl)-3-[4-(2-methoxyphenyl)piperazine-1-y l]propoxy}benzoyl}indole-1-yl}butyric acid hydrochloride] were investigated in rabbits and rats in vivo. Z-350 (1-30 mg/kg), administered intraduodenally, dose-dependently inhibited phenylephrine-induced increases in prostatic urethral pressure with an ED(50) value of 3.8 mg/kg in anesthetized male rabbits, whereas the effects on mean blood pressure and orthostatic hypotensive response were weaker when compared with other alpha(1)-adrenoceptor antagonists, tamsulosin and prazosin. Z-350 (1-10 mg/kg p.o.) dose-dependently inhibited the prostatic steroid 5alpha-reductase activity in rats with an ED(50) value of 2.8 mg/kg. The daily oral administration of Z-350, at >==10 mg/kg for 7 days, significantly reduced the prostatic growth induced by testosterone in castrated rats, with no effect on dihydrotestosterone-induced prostatic growth. These results indicate that Z-350 exhibited alpha(1)-adrenoceptor-antagonistic and 5alpha-reductase inhibitory actions at almost equal doses in vivo, and was expected to improve the bladder outlet obstruction associated with benign prostatic hyperplasia with smaller cardiovascular adverse effect.

Arachidonic acid-induced hind limb gangrene: a new experimental rat model of peripheral vascular disease.

The purpose of this study was to investigate the characteristics of arachidonic acid-induced peripheral vascular disease in rats. Injecting arachidonic acid (2 mg/leg) into the femoral artery caused hind limb gangrene. Histopathological examination revealed occlusive thrombi and marked vascular injury, including denudation of the endothelium and degeneration of the media in the paw arteries. Arachidonic acid injection markedly enhanced the platelet response to both U-46619 and collagen. Although the number of circulating platelets did not differ between sham-operation rats and arachidonic acid-injected rats, the numbers of circulating white blood cells and red blood cells were raised 10 d after arachidonic acid injection. Thrombocytopenia, induced before arachidonic acid injection, markedly suppressed arachidonic acid-induced hind limb gangrene in rats. In addition, the combined administration of aspirin (100 mg/kg/d, p.o.) and ticlopidine (300 mg/kg/d, p.o.) prevented the progression of arachidonic acid-induced hind limb gangrene. These results suggest that platelets are involved in the progression of arachidonic acid-induced hind limb gangrene. This experimental rat model may be suitable for developing novel drugs for the treatment of peripheral vascular disease.

Z-335, a thromboxane A2 receptor antagonist, suppresses the progression of arachidonic acid-induced hind limb gangrene in rats.

We have developed a new rat model of gangrenous peripheral vascular disease with vascular injury and occlusive thrombi. Rat hind limb gangrene was induced by injecting arachidonic acid (2 mg/leg) into the femoral artery. Using this model, we evaluated the effect of a thromboxane A2 receptor antagonist, Z-335, on the progression of hind limb gangrene. Z-335 (10 mg/kg/d, p.o.) ameliorated arachidonic acid-induced hind limb gangrene. In contrast, daltroban (10 mg/kg/d, p.o.) and cilostazol (100 mg/kg/d, p.o.) tended to improve the hind limb gangrene but their effects failed to reach statistical significance. Z-335 (10 mg/kg, p.o.) inhibited U-46619-induced, but not collagen-induced, platelet aggregation in rat whole blood. Daltroban (10 mg/kg, p.o.) showed a tendency to inhibit U-46619-induced platelet aggregation. Cilostazol (100 mg/kg, p.o.) did not inhibit U-46619- or collagen-induced platelet aggregation. Histopathological examination of the injured paws showed that Z-355 (10 mg/kg, p.o.) had partly inhibited the formation of occlusive thrombi. These results indicate that the thromboxane A2 receptor antagonist Z-335 is effective against arachidonic acid-induced hind limb gangrene in rats. Our experiments suggest that Z-335 may be beneficial in the prevention of gangrenous peripheral vascular disease.

A new thromboxane receptor antagonist, Z-335, ameliorates experimental thrombosis without prolonging the rat tail bleeding time.

We investigated the antithrombotic activity of Z-335, a new thromboxane A2 receptor antagonist, using experimental thrombosis models, and also tested its effect on the rat tail bleeding time. Z-335 (0.1, 0.3, and 1 mg/kg, p.o.) dose-dependently prevented the occurrence of arachidonic acid-induced pulmonary thromboembolism in mice. During photochemically induced thrombosis in the femoral artery of guinea pigs, Z-335 (0.3, 1, and 3 mg/kg, i.v.) dose-dependently prolonged the time required to form thrombi. Moreover, Z-335 (10 mg/kg/day, p.o.) strongly suppressed lauric acid-induced hind limb injury in rats. Z-335 (0.3, 3, 30, and 300 mg/kg, p.o.) did not prolong the tail bleeding time in rats. These results strongly suggest that Z-335 ameliorates experimental thrombosis without prolonging the rat tail bleeding time, and may therefore be a useful antithrombotic drug.

Antiplatelet effect of Z-335, a new orally active and long-lasting thromboxane receptor antagonist.

We investigated the pharmacological characteristics of Z-335 ((+/-)-sodium[2-[4-(chlorophenylsulfonylaminomethyl)indan-5-yl]ace tate monohydrate), a new indan derivative. Z-335 inhibited the specific binding of [3H]SQ-29548 to human platelets and guinea pig platelet membranes. The IC50 values of Z-335 for human platelets and guinea pig platelet membranes were 29.9 +/- 3.1 nM with a slope of 1.09 +/- 0.05 and 32.5 +/- 1.7 nM with a slope of 1.07 +/- 0.02, respectively. Z-335 inhibited thromboxane A2 receptor-mediated human and guinea pig platelet aggregation in vitro and oral administration of this drug to guinea pigs inhibited U-46619- and collagen-induced platelet aggregation for 24 h. Z-335 dose-dependently prevented the occurrence of U-46619-induced pulmonary thromboembolism in mice and the protective effect of this drug (0.3 and 3 mg/kg, p.o.) lasted for 24 h. These results strongly suggest that Z-335 is a potent, orally active and long-lasting thromboxane A2 receptor antagonist, which may be useful as an antiplatelet drug.

Inhibitory effects of efonidipine hydrochloride on contraction induced by several vasoconstrictors in porcine coronary artery: comparison with effects of nifedipine and nisoldipine.

We studied the effects of efonidipine hydrochloride (efonidipine), a 1,4-dihydropyridine derivative, on contractions induced by high-K+ solution (high K+), serotonin (5-HT), U46619, which is a stable analog of thromboxane A2, and endothelin-1 (ET-1) in comparison with those of nifedipine and nisoldipine in porcine coronary arteries. The effects of the drugs were compared after 1- and 3-h incubations. Efonidipine, nifedipine, and nisoldipine each inhibited the contractions induced by these vasoconstrictors. The inhibition of high-K(+)- and 5-HT-induced contractions by efonidipine, but not by nifedipine and nisoldipine, increased when the incubation time was prolonged, whereas the inhibition of U46619- and ET-1-induced contractions was not altered. The potency of efonidipine on U46619- and ET-1-induced contractions was greater than that of nifedipine and equivalent to that of nisoldipine. Thus the inhibitory effect of efonidipine on U46619- and ET-1-induced contractions seems to be stronger than its effects on high-K(+)- or 5-HT-induced contractions, in contrast to the effects of other dihydropyridines. In an additional series of experiments, efonidipine did not inhibit U46619-induced contractions in Ca2(+)-free solution or in the presence of nifedipine. Moreover, efonidipine did not inhibit the specific binding of [3H]SQ 29,548, a thromboxane A2 antagonist, to porcine coronary arterial membrane. Therefore we think that the inhibitory effect of efonidipine on contractions induced by vasoconstrictors was caused by blockade of Ca2+ influx through L-type Ca2+ channels. However, some unknown mechanism(s) in addition to this effect on Ca2+ channels may contribute to the effect of efonidipine on U46619- and ET-1-induced contractions.

Spasmolytic effect of efonidipine hydrochloride in isolated canine coronary artery: comparison with the effects of nifedipine and nisoldipine.

Spasmolytic effects of efonidipine hydrochloride (efonidipine) on high K(+)-, U46619- and 3,4-diaminopyridine (3,4-DAP)-induced contractions were evaluated in isolated canine coronary, artery, and were compared with the effects of nifedipine and nisoldipine. Efonidipine (0.3-30 nM), nifedipine (1-300 nM) and nisoldipine (0.1-100 nM) each relaxed the contractions induced by high K+ and U46619. However, relaxation produced by efonidipine was slower than that produced by nifedipine or nisoldipine. The rank order of potency of these drugs for U46619-induced contraction was efonidipine > or = nisoldipine > nifedipine, whereas in high K(+)-induced contraction, it was nisoldipine > efonidipine > nifedipine. Thus, the relaxing effect of efonidipine on U46619-induced contraction appeared to be more potent than its effect on high K(+)-induced contractions, when compared with the effects of nifedipine and nisoldipine. These three drugs also suppressed 3,4-DAP-induced rhythmic contractions. However, a marked time-dependent increase in potency was only observed for efonidipine, and was similar to its time-dependent effect on high K(+)- and U46619-induced contractions. Efonidipine did not change the contraction cycle length whilst suppressing the peak contractions. On the other hand, lower concentration of nifedipine at 3 nM and nisoldipine at 1 nM significantly shortened the cycle length. These results suggest that efonidipine may be an effective agent for the treatment of angina pectoris. The high potency of efonidipine for U46619-induced contractions will provide some advantages in the clinical use of this compound on thromboxane A2-mediated coronary vasoconstriction.

[Effect of efonidipine hydrochloride (NZ-105) on modification of low density lipoprotein induced by rat cultured endothelial cells].

We studied the effects of efonidipine hydrochloride [NZ-105: (+/-)-2-[benzyl (phenyl) amino] ethyl 1,4-dihydro-2,6-dimethyl-5-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorina n-2- yl)-4-(3-nitro-phenyl)-3-pyridinecarboxylate hydrochloride ethanol] and nisoldipine on endothelial cell-induced low density lipoprotein (LDL) modification. The modification of LDL by cultured rat endothelial cells was performed by incubating 3 micrograms protein/well LDL with 5 microM CuSO4 for 24 hr at 37 degrees C in the presence of confluent cells. The extent of modification was assayed by measuring the thiobarbituric acid-reactive substances (TBARS). Efonidipine hydrochloride reduced the TBARS level in a dose-dependent manner. At 3 x 10(-7) M, efonidipine hydrochloride showed a significant effect. On the other hand, the significant effect of nisoldipine was observed only at 10(-5) M. Thus the action of efonidipine hydrochloride on the inhibition of LDL-modification was much more potent than that of nisoldipine. As the modification of LDL was thought to play a key role in the initiation and progression of atherosclerosis, efonidipine hydrochloride may be useful against atherosclerosis.

Bioavailability of calcium from calcium carbonate, DL-calcium lactate, L-calcium lactate and powdered oyster shell calcium in vitamin D-deficient or -replete rats.

The bioavailability of calcium from various calcium sources in humans and animals has been the subject of investigation for many years and there is considerable controversy as to the relative bioavailability of different calcium salts. Most of the studies have used a calcium balance technique which has numerous problems in terms of performance and interpretation. Using a method for evaluating the efficacy of calcium from calcium salts used for plasma calcium metabolism and bone mineralization, we examined the bioavailability of calcium from four commercially available calcium salts, namely calcium carbonate, DL-calcium lactate, L-calcium lactate and powdered oyster shell-calcium in vitamin D-deficient or -replete rats. Among the calcium salts, the differences in bioavailability were small and not statistically significant as tested by analysis of variance in both groups of rats. Thus, we conclude that calcium is utilized to the same extent from calcium carbonate, DL-calcium lactate, L-calcium lactate and powered oyster shell-calcium in both vitamin D-deficient and -replete rats.