Simvastatin and atorvastatin enhance hypotensive effect of diltiazem in rats.

Effects of the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, simvastatin and atorvastatin, on diltiazem-induced hypotension were examined in anaesthetized rats and compared to that of pravastatin. Vehicle, 2 mg/kg/day simvastatin, 2 mg/kg/day atorvastatin, or 4 mg/kg/day pravastatin was administered orally for 4 days. Diltiazem at 3 mg/kg was given orally 2 hours after the final administration of the inhibitors. Arterial blood pressure was measured via a cannula introduced into the left carotid artery, and heart rate was counted from the pulse pressure. In all groups, diltiazem significantly decreased the mean arterial blood pressure without any changes in heart rate. Pretreatment with simvastatin and atorvastatin significantly enhanced the hypotensive effect of diltiazem, while that with pravastatin did not. Heart rate was not modified by pretreatment with the inhibitors. The results indicate that concomitant use of diltiazem with simvastatin or atorvastatin enhances diltiazem-induced hypotension, probably by competitive inhibition of diltiazem metabolism with simvastatin and atorvastatin metabolisms.

Reproductive effects of nonylphenol in rats after gavage administration: a two-generation study.

The potential reproductive toxicity of nonylphenol (NP) was assessed in a two-generation reproductive toxicity study. Groups of 25 male and female Crj:CD (SD) IGS rats were given NP by gavage at levels of 2, 10, or 50 mg/kg, and 25 males and females were given corn oil as controls. No adverse changes in clinical signs were observed in any rats throughout the study. Significant increases in the liver, kidney and pituitary gland weights in males, and decreases in thymus weight in males and in ovary weight in females were observed in the 50 mg/kg group. NP did not affect sperm characteristics or the estrous cycle at any dose administered. A significant increase in the TSH level was observed in males in the 50 mg/kg group. No adverse effects of NP on reproduction were found. At necropsy, no treatment-related alterations were observed in any organs including the reproductive tissues in any group. Histopathologic changes were found in the liver of male and female rats and kidneys of males in the 50 mg/kg group. The viability of offspring from postnatal day 0 to 4 in the 50 mg/kg group was reduced as compared with that in the controls, although growth was not affected by NP administration. On postnatal day 22, an increase in the serum FSH level and decrease in T(3) level for males, and decreases in LH and TSH levels and an increase in T(3) levels for females were observed in the 50 mg/kg group. NP did not affect the timing of preputial separation, while vaginal opening was accelerated in the 50 mg/kg group. No adverse changes were found in behavior or learning in the offspring of NP-treated groups. There were no treatment-related changes in any reproductive parameter, including estrous cycle, mating, fertility, delivery, and lactation, except for significant decreases in the numbers of implantation sites and live pups, and a significant decrease in ovary weight in the 50 mg/kg group. Kidney and liver weight were increased in males in the 50 mg/kg group. Histopathologic examination revealed changes in the liver of males and females of the 50 mg/kg group. No treatment-related changes were observed in the sperm characteristics. Hormone data should be interpreted cautiously until the findings are repeated and confirmed by further studies. These results of NP suggested that the no observed adverse effect level (NOAEL) on reproductive capacity is 50 mg/kg/day or greater in parent animals, and 10 mg/kg/day in the next generation under the present experimental condition.

Effect of butyl benzyl phthalate in Sprague-Dawley rats after gavage administration: a two-generation reproductive study.

Butyl benzyl phthalate (BBP), a plasticizer, has been shown in in vitro studies to be weakly estrogenic, and in in vivo studies to possess testicular toxicity and teratogenicity, but few experimental data on BBP multigeneration effects on reproduction in mammals are available. The present two-generation reproductive study was conducted in male and female Sprague-Dawley rats using oral doses of 0, 20, 100, and 500 mg/kg/day BBP. Endpoints were chosen in order to evaluate both subchronic and reproductive toxicity. In the parent animals (F(0)), a decrease in body weight gain was observed in males in the 500 mg/kg/day group, although no significant decrease in food consumption was found. No dose-related changes were observed in estrous cyclicity, fertility, or lactation. A dose-dependent increase in kidney weight in rats of both sexes, an increase in liver weight in males, and a decrease in the weight of the ovaries in females were observed. No macroscopic or microscopic changes were found in the reproductive system of males or females. Oral administration of BBP caused a decrease in the serum concentration of testosterone, and an increase in FSH. In the next generation (F(1)), the body weight of male and female offspring at birth in the 100 and 500 mg/kg groups was significantly decreased, and the body weight in the 500 mg/kg group was lower throughout the study, while viability was not affected. Anogenital distance (AGD) at birth was decreased in male pups and was increased in female pups of the 500 mg/kg/day group. Preputial separation for male offspring in the 500 mg/kg/day group was delayed, while vaginal opening for female offspring in this group was not affected. BBP did not affect reproductive ability, including delivery and lactation, at any dose whereas macroscopic and microscopic changes of the testis, and decreased serum concentrations of testosterone were observed in male offspring of the 500 mg/kg/day group after puberty. From these data, it would appear that 20 mg/kg BBP is a no observed adverse effect level (NOAEL) for reproductive effects on parent animals and the next generation.

Influence of corn oil and diet on reproduction and the kidney in female Sprague-Dawley rats.

The purpose of this study was to investigate the influence of corn oil administration on gestation, parturition, and lactation in rats, in conjunction with diets differing in composition of nutrients. Rats were divided into two groups, each fed different commercial pellets for rodents, CA-1 or CE-2, different from each other mainly in the source of protein. Female Sprague-Dawley rats in both diet groups were administered 0 (untreated control), 2, or 10 ml corn oil/kg body weight by gavage during the premating period (2 weeks), the mating period, the gestation period, and the lactation period (until day 3 of lactation). Food consumption of both the 10 ml/kg corn oil groups was significantly reduced throughout the study. Body weight gain in the 10 ml/kg corn oil group fed the CA-1 diet was significantly reduced on days 0 through 4 of lactation. Neither mating nor fertility indices were affected, and no clinical signs were observed during the gestation period in any groups. Several dams in the 10 ml/kg corn oil group fed the CA-1 diet, however, showed abnormal conditions after parturition, and three dams became moribund. Pup viability was also reduced in this group. Histopathologic examination of the kidneys of dams in the 10 ml/kg corn oil group fed the CA-1 diet revealed severe lesions in the proximal tubular epithelium, i.e., necrosis and fatty degeneration. Females in any group fed the CE-2 diet showed neither abnormal condition after parturition nor any severe lesions in the kidney. These data show that the combination of corn oil and diet with a particular constitution may cause adverse effects on the renal tubules in pregnant and/or lactating rats, suggesting that corn oil gavage as a vehicle can be a confounding factor in the reproductive toxicity studies, depending on the diet.

Effects of food restriction on reproductive and toxicological parameters in rats--in search of suitable feeding regimen in long-term tests.

Eighty Sprague-Dawley rats, consisting of 40 animals of each sex, were examined for age-related lesions after a 13-week food restriction. From 6 weeks of age, four groups of 10 male and 10 female rats each were fed normal pelleted chow, ad libitum for the control group and approximately 85%, 70% and 55% of feed consumption in the control group, for 13 weeks. Estrous cycles in females were examined during the 3rd through 12th week of the study, and hematological, blood biochemical and pathological examinations of all animals were carried out after the 13-week feeding. Estrous cycles were prolonged or stopped in most females of the 55% feeding group from the 7th week of restricted feeding and atrophy of the theca granulosa cells with decreased cytoplasmic lipid droplets was found in the ovaries at necropsy. In the males of the 55% feeding group, Leydig cell atrophy was found in the testes. The groups at 70% and 85% feeding showed no abnormality in hematological, blood biochemical and pathological observations. On the other hand, decreases in plasma lipid peroxide levels were noted in the 70 and 85% feeding groups. These results suggest that 70% and 85% feedings seem suitable for minimizing development of age-related changes without nutritional disorders.

Testicular development and fertility of mice treated prenatally with N-nitroso-N-ethylurea at various gestational stages.

N-nitroso-N-ethylurea (ENU) was injected intraperitoneally (i.p.) into ICR female mice at 50 mg/kg on day 8, 10, 12, or 16 of gestation (plug day = day 0). Male newborns treated prenatally with ENU were obtained. Body and testes weights of males were measured on postnatal days 4, 12, and 21 and at 12 weeks of age, as well as histopathological observation of their testes. The treated males were mated at 10 weeks to untreated females of the same strain. Subsequently, the plasma testosterone concentration in each group was determined by enzyme immunoassay. Body weight on postnatal day 4 in the group treated on day 16 of gestation was significantly lower compared to that of the control group. On postnatal day 21 and at 12 weeks of age, body weight was significantly lower in all groups treated with ENU compared to that of the control group. Among the embryonic stages tested, embryonic day 10 is the most susceptible to ENU insult with respect to the postnatal development of testes and epididymides, when judged by the relative weight at 12 weeks of age. The fertility of the male offspring was drastically impaired by the prenatal ENU treatment on embryonic day 10, followed by day 12, while the fertility of male offspring treated on embryonic days 8 and 16 was not affected. Histopathological sections of testes of male offspring treated with ENU on embryonic day 10 resulted in the most severe changes in the seminiferous tubules. The plasma testosterone concentration was drastically lower in male offspring treated on embryonic day 10 compared to the control level. These results demonstrate that the impaired fertility of the ENU-affected mice was the result of paucity of germ cells and that the critical period in the male mouse fetus with respect to the disturbance of postnatal testicular development and fertility was around embryonic day 10, which is the period of primordial germ cell migration.

[Influence of fetal position on respiratory function and its modification by epidural anesthesia in supine pregnant women].

We investigated the influence of fetal position on respiratory function and its modification by epidural anesthesia in supine pregnant women. We found that supine pregnant women in whom the fetus was in the right occipital anterior position (ROA) had lower inspiratory reserve volume (IRV) and vital capacity (VC) than controls in whom the fetus was in the left occipital anterior position (LOA). When the analgesic level was up to Th7 or lower, epidural anesthesia increased the VC of women with a ROA fetus and also increased IRV. With higher analgesic levels up to Th4-Th6, tidal volume (TV) and VC increased independently of fetal position. We speculate that the pressure caused by the ROA fetus on thorax of the mother is stronger and that after epidural anesthesia this pressure decreases even though the analgesic level is low, and with the analgesic level up to Th4-Th6, the level used for Cesarean section, the displacement of the uterus makes respiration during rest easier regardless of fetal position.

Effects of N-(4-methylbenzylthiocarbonyl)-L-phenylalanine (KF 1492), a new hypolipidemic drug, and clofibrate on lipids metabolism.

The effects of N-(4-methylbenzylthiocarbonyl)-L-phenylalanine (KF 1492) on the intestinal lipid absorption, the biliary lipid composition and alpha-glycerophosphate dehydrogenase (GPD) activity have been investigated in rats in comparison with clofibrate. KF 1492 did not have inhibitory activity on intestinal absorption of cholesterol and triglyceride. In the KF 1492-treated group (100 mg/kg, 8 d), an increase of bile flow (25.9%) per g liver was observed. The increase of excretion of bile acids (29.9%), phospholipids (45.2%) and cholesterol (33.4%) due to the increase of bile flow was clearly observed but no significant change in the concentration of each lipid was observed. In clofibrate-treated group, the concentration of bile acids and cholesterol in bile was decreased and output of biliary phospholipids was increased. Approximately 5 to 10 times increase of GPD activity was observed in mitochondrial fraction of the KF 1492- or clofibrate-treated rats (0.25% (w/w) in rat chow, 3 weeks). Thus, the increased degradation and excretion of cholesterol to bile may explain the hypocholesterolemic activity of KF 1492.

Lipid-lowering effects of N-[4-methylbenzylthiocarbonyl]-L-phenylalanine (KF1492), a new phenylalanine derivative.

Lipid-lowering effects of KF1492, N-[4-methylbenzylthiocarbonyl]-L-phenylalanine, were evaluated in comparison with clofibrate. This compound lowered serum cholesterol (s-CL) and triglyceride(s-TG) in cholesterol-fed, Triton-injected and glycerol-fed rats as well as in normal rats. The dose of KF1492 required to show these effects was almost equal to that of clofibrate. In addition, KF1492 produced significant reductions of s-CL and s-TG in thiouracil-fed rats and decreasing phase of Triton-induced hyperlipemia of rats. In these models, clofibrate produced no significant reductions. Clofibrate produced a marked increase of liver size and shortened the pentobarbital-induced sleeping time in rats. On the contrary, the increase of liver size by KF1492 was less marked than clofibrate, and KF1492 caused no change in the sleeping time. Thus, it is apparent that KF1492 is a new lipid-lowering compound with less hepatic effect than clofibrate and that the lipid-lowering profile of KF1492 differs from that of clofibrate in some points.

Distribution and excretion of 7-N-(p-hydroxyphenyl)-mitomycin C in normal mice.

Tissue distribution, excretion and stability of 7-N-(p-hydroxyphenyl)-mitomycin C (M-83) in normal mice were compared with those of mitomycin C (MMC) by microbiological assay. M-83 was more rapidly inactivated by mouse liver homogenate in vitro than MMC. MMC could not be detected by thin-layer chromatography-bioautography in the reaction mixture of M-83 incubated with mouse liver homogenate, or in the mouse urine. Both M-83 and MMC exhibited biphasic serum elimination characteristics after iv bolus injection. When these compounds were administered at their approximate LD50 (M-83, 20 mg/kg; MMC, 8 mg/kg) iv into mice, their half-lives were 17.9 and 19.8 min, respectively. However, the half-life of M-83 (10.2 mg/kg) after iv bolus injection was 7.5 min and was shorter than that of MMC (8 mg/kg) at the molar equivalent dose. In ip administration of an approximate LD50, M-83 and MMC exhibited similar drug absorption and elimination patterns. When both compounds were administered iv at the approximate LD50, the 24-hr urinary recoveries of unchanged M-83 and MMC were 2.85 and 19.26%, respectively. The distribution of M-83 in various tissues was similar to that of MMC.

Effect of N-acetyl-L-glutamine aluminum complex (KW-110), an antiulcer agent, on the non-steroidal anti-inflammatory drug-induced exacerbation of gastric ulcer in rats.

Gastric ulcer induced by the injection of acetic acid (0.025 ml of 20%) into the gastric wall of rats was healed considerably 5 days after the injection of acetic acid. Non-steroidal anti-inflammatory drugs (NSAID) such as aspirin, indomethacin, and phenylbutazone were given consecutively for 5 days, and they exacerbated the ulcer and enlarged the ulcer area. Aspirin caused exacerbation when it was given for the initial 5 days of the ulcer healing process. Phenylbutazone caused exacerbation by the administration for 5 days at the middle stage of the ulcer healing process. In contrast, indomethacin caused exacerbation not only when it was given for the initial 5 days but also when it was given for the middle 5 days. The effect of the antiulcer agent N-acetyl-L-glutamine aluminum complex (KW-110) on the exacerbation was studied. KW-110 at an oral dose of 500 mg/kg inhibited remarkably the exacerbation induced by all of the NSAID used. The development of gastric lesions induced by these NSAID was also prevented by KW-110. Further study was carried out with regard to the influences of KW-110 on the pharmacological properties of NSAID. The results showed no influences of KW-110 on the antiedematous and antipyretic actions of the NSAID.

Chemo-immunotherapy of methylchoranthrene-induced fibrosarcoma by concanavalin A-bound tumor vaccine, levamisole and mitomycin C.

Concanavalin A (ConA)-bound-tumor cell vaccine of methylchoranthrene-induced fibrosarcoma (Meth 1) induced tumor-specific immunoprophylactic and immunotherapeutic response against an inoculum of live Meth 1 cells in histocompatible animals. ConA-free Meth 1 vaccine induced much less response under the identical experimental conditions. Immunotherapeutic potency of ConA-bound Meth 1 vaccine was enhanced by levamisole, and 37% of the animals inoculated with 10(4) live Meth 1 cells at day 0 were cured when they were administered 10(6) cells of ConA-bound Meth 1 vaccine at days 1 and 8 and 0.63 mg/kg levamisole at days 1,2 and 3. Delayed administration of levamisole at day 8,9 and 10 was less effective than the earlier administration, but still produced a 17% cure of Meth 1-bearing animals when combined with ConA-bound Meth 1 vaccine. Immunotherapeutic response under these regimens was further enhanced by mitomycin C, and approximately 60% of the animals inoculated with 10(5) Meth 1 cells were cured when three agents were administered at the defined intervals. These results suggest the feasibility of the regimen in which the therapeutic response induced by immunotherapeutic agents is further enhanced by the selected chemotherapeutic agents.

Effects of N-(4-methylbenzylthiocarbonyl)-L-phenylalanine (KF 1492), a new phenylalanine derivative on lipid synthesis in vivo, inhibition of hepatic cholesterol synthesis and 3-hydroxy-3-methylglutaryl-Co A reductase.

KF 1492, a new phenylalanine derivative, was administered at a dose of 100 mg/kg or 0.25% (w/w) diet to Wistar rats. After different periods of drug administration, incorporation of 14 C-acetate or 14 C-mevalonic acid into digitonin-precipitable sterols and hepatic 3-hydroxy-3-methylglutaryl-Co A (HMG-CoA) reductase activity were measured. KF 1492 feeding was associated with depressed incorporation of 14 C-acetate into sterols in liver slices or homogenate. There was no effect on incorporation of 14 C-mevalonic acid into sterols. Thus, KF 1492 administration induced inhibition of hepatic HMG-CoA reductase correlated with reduction of incorporation of 14 C-acetate into digitonin-precipitable sterols. KF 1492 feeding also inhibited in vivo sterol synthesis in rats, which was intraperitoneally injected with 14 C-acetate. Stereoisomers, metabolites adn chemically similar compounds of KF 1492 reduced HMG-CoA reductase activity, and this was correlated with lowering the activity of plasma cholesterol. These findings indicate that a major site of the action of KF 1492 in the inhibition of sterol synthesis may be at the level of HMG-CoA reductase.

Antitumor activity of 7-n-(p-hydroxyphenyl)-mitomycin C in experimental tumor systems.

The antitumor activity of 7-N-(p-hydroxyphenyl)-mitomycin C (M-83) was compared with that of mitomycin C (MMC) in rodent tumor systems. M-83 exhibited more potent activity than MMC against the ascitic form of lymphocytic leukemia P388 and fibrosarcoma Meth 1, and doses of over 5 mg/kg of M-83 (1/6 LD50) resulted in some 60-day survivors. The chemotherapeutic ratio (optimal dose/MED) of M-83 was around 64 and was estimated to be approximately 5 to 8 times higher than that of MMC. Upon intravenous administration, M-83 also gave a better survival and showed a higher chemotherapeutic ratio than MMC against intravenously implanted P388. M-83 inhibited the growth of solid form of sarcoma 180 to the same extent as MMC at an equivalent dose, but showed a higher safety margin than MMC. M-83 was as effective as MMC against Lewis lung carcinoma at dose levels giving the same degree of toxicity. In vitro studies on tumor growth inhibition demonstrated that the cytotoxic effects of M-83 against leukemia P388 and fibrosarcoma Meth 1 cells were similar to and stronger than those of MMC, respectively.

Gilvocarcins, new antitumor antibiotics. 3. Antitumor activity.

Gilvocarcin V, isolated rom a Streptomyces culture showed activity against experimental tumors such as sarcoma 180, Ehrlich carcinoma, Meth 1 fibrosarcoma, MH134 hepatoma and lymphocytic leukemia P388. In particular, 40% of treated mice survived for 60 days, after intraperitoneal administration of gilvocarcin V to mice bearing Ehrlich ascites carcinoma. But it was marginally active against B16 melanoma and did not produce prolongation of lifespan of mice bearing Lewis lung carcinoma.