The influence of Viburnine on red blood cell metabolism and hemoglobin oxygen affinity was investigated in normobaric rats (FiO2 : 10%). Two periods of hypoxic exposure were performed (10-21d). In each experimental series, rats were divided into two groups : Treated rats received a daily intraperitoneal injection of drug (4 mg/kg). Control rats in the same conditions of hypoxia received an isotoic saline solution.For a 10 d exposure period, Vinburnine does not affect red blood cell metabolism nor hemoglobin oxygen affinity. At 21 d period exposure, 2, 3 diphosphoglycerate (2, 3 DPG) and ATP amounts increase in treated rats. The rate of increase was 10% (p<0.05) and 28% (p<0.01), respectively. Red blood cell metabolism effect of Vinburnine was not accompanied by a modification in affinity hemoglobin oxygen (Hb-O2); no statistically significant difference was observed between treated rats and control rats concerning p50 (partial pressure oxygen at half hemoglobin saturation).Results suggest that Vinburnine has a metabolic effect corresponding to a glycolysis anaerobic stimulation, which can improve oxygen delivery to tissues and could explain the favorable hemoreological action of Vinburnine observed in a previous investigation.
The influence of long-term n-3 fatty acid deficiency on the rate of protein synthesis in rat brain and liver was investigated in relation to learning behavior or a presumed survival time-shorttening factor (SSF) in rapeseed oil, using a large-dose [3H]phynylalanine (Phe) injection method. When Wister rats were made n-3 fatty acid-deficient by feeding a safflower oil (α-linolenate-deficient) diet for 2 generations, conditions under which the safflower oil group had been shown to exhibit altered learning behaviors, compared with the perilla oil group, no significant changes in the rate of protein synthesis were observed compared with the perilla oil (α-linolenate-sufficient) of rapeseed oil (α-linolenate-sufficient but SSF-containing) groups. However, the rapeseed oil group had a reduced specific raioactivity of free Phe in the cerebral cortex, compared with the safflower oil group. In contrast to the reported oservation of very long-term n-3 fatty acid deficiency inducing an almost 2-fold increase in the rate of protein synthesis in the brain, our results indicate that altered learning behavior resulting from n-3 fatty acid deficiecy in rats is not associated with any substantial changes in the rate of protein synthesis in the brain.
A vanadyl sulfate-bovine serum albumin complex (vanadyl-BSA) prolonged the stability of the V4+ oxidation state, although vanadyl alone can readily change the oxidation state from V4+ to V5+ under physiological conditions. Vanadyl-BSA stimulated the release of lipoprotein lipase (LPL) acitivty from isolated rat fat pads and increased the cellular LPL activity in a time-dependent manner. These effects were independent of protein synthesis. Propranolol, quin 2-AM, ruthenium red, and neomycin all inhibited LPL release more potently than the increase in activity. In contrast, potent inhibition of the increase effect was observed with genistein and wortmannin. Short-term incubation of the fat pads with vanadyl-BSA showed a transient increase in the cellular content of cAMP and myo-inositol 1, 4, 5-triphosphate (IP3), which was inhibited by propranolol and neomycin, respectively. These results suggest that vanadyl-BSA stimulates the release of LPL activity through an increase in the cellular content of cAMP and IP3, leading to an increased intracellular Ca2+ concentration, and tat it also increases cellular LPL activity via process(es) sensitive to genistein and wortmanni.
Ruminococcus sp. PO1-3, an intestinal bacterium isolated from human feces, metabolized glycyrrhizin (GL) to glycyrrhetic acid (GA) and GA to 3-oxo-glycyrrhetic acid (3-oxo-GA) and possessed GL β-D-glucuronidase and 3β-hydroxysteroid dehydrogenase (3β-HSD) involved in the metabolism of GL. This bacterial growth was enhanced by GL at a concentration of 0.4 mM and was suppressed by GA at concentration of 1.0 mM. henodeoxycholic acid, deoxycholic acid and lithocholic acid among the bile acids added to this bacterium suppressed the growth ad GL β-D-glucuronidase activity and 3β-HSD activity incident to it at a concentration of 1.0 mM, while cholic acid, hyodeoxycholic acid and glycine and taurin conjugates of cholic acid, chenodeoxycholic acid, deoxycholic acid and lithocholic acid had almost no effect on this bacterium at a concentration of 2.0 to 1.0 mM. However, these enzyme activities of this sonicated bacteria were inhibited by all of these bile acids. Althrough each bile acid and GL added to bacteria at the same time supressed the growth and te amount of metabolite GA by all bile acids used except cholic acid, taurocholic acid and taurodeoxycholic acid with GL, a combination of each bile acid and GA eased the growth inhibition caused by GA at a concentration of 2.0 mM and enhanced the amount of metabolite 3-oxo-GA by the glycine conjugate of bile acids with GA. GL or GA added after 6 h culture with each of these bile acids and bacteria was metabolized to a relatively large amount of GA by chenodeoxycholic acid and lithocholic acid and their glycine and taurine conjugates, glycocholic acid and taurodeoxycholic acid, or had almost no effect on the amount of metabolite 3-oxo-GA, respectively. These results showed that although GL added after the exposure to bile acid and GA and bile acid added at the same time as bacteria had different bile acid action, these conditions enhanced the amount of metabolite GA from GL and metabolite 3-oxo-GA from GA.
The distribution of low molecular weight phosphotyrosine protein phosphatase (LMW-PTP) in subcellular fractions of rat brain tissue was investigated by immunoblotting analysis using anti-LMW-PTP antibody. The enzyme was detected in the 105000 g precipitate in addition to the supernatant of brain homogenate, even after the precipitate was extensively washed, and was abundant in the particulate fraction of nerve endings. Nerve ending LMW-PTP was effectively solubilized by 1% Triton X-100 or 1% deoxycholate, though the enzyme was solubilized by thorough sonication. Two forms of LMW-PTP, designated as LMW-PTP-I and -II, were separated from the nerve ending-rich fraction by chromatofocusing. Nerve endings PTP-I and -II were different in molecular weight, isoelectric point and susceptibility to activators and inhibitors. The properties of nerve endings LMW-PTP-I and -II were similar to those of cytosolic LMW-PTP-I and -II. The abundance of LMW-PTP in nerve endings as well as in the cytosol suggests that this enzyme plays an important role in synaptic function.
NADPH oxidase was activated by arachidonate in a cell-free system consisting of membrane and cytosol fractions prepared from guinea pig neutrophils. Vanadate apparently inhibited the NADPH oxidase activity in the cell-free system (IC50=2 μM) without phosphotyrosine accumulation. The pH dependency and stability of the inhibitory effect observed for vanadate solution indicated that decavanadate, an isopolyanion of vanadate, was responsible for the inhibition. Pervanadate (vanadyl hydroperoxide) also inhibited the oxidase activity but at a higher concentration (IC50=0.2 mM). Decavanadate lowered the Vmax but did not affect the Km value of NADPH oxidase for NADPH. Decavanadate inhibited the activation process of NADPH oxidase but not the oxidase activity itself. Decavanadate-pretreatment of membrane and cytosol fractions irreversibly decreased the abilities of both fractions to activate NADPH oxidase in the cell-free system. Translocation of p47-phox, one of the cytosolic activation factors of NADPH oxidase, from cytosol to membrane, was little effected by decavanadate. These results suggest that decavanadate inhibits the activation of NADPH oxidase in the cell-free system without affecting the phosphotyrosine phosphatase, and that decavanadate can bind to both the membrane and cytosolic activation factors when they are in a dormant stat, but not to the active oxidase complex.
The effect of genistein on osteoclase-like multinucleated cells (MNCs) from rat femoral tissues was investigated. When rat marrow cells were cultured for 7 d in a medium containing either vehicle, parathyroid hormone (10-8 M) or prostaglandine E2 (10-6 M), the formation of tartrate-resistant acid phosphatase (TRACP)-positive MNCs was significantly increased. This increase was markedly weakened by the presence of genistein (10-6 or 10-5 M). The bone cells isolated from rat femoral tissues were cultured for 48 h in an α-minimal essential medium (5% fetal bovine serum) containing either vehicle or genistein (10-8 to 10-5 M). Osteoclasts were estimated by staining for TRACP, a marker enzyme of osteoclasts. The presence of genistein caused a significant decrease in the number of osteoclasts. Such a decrease was also seen in the presence of calcitonin (10-10 to 10-8 M), dibutyryl cyclic adenosine 5'-monophosphate (DcAMP; 10-6 and 10-5 M), calcium chloride (10-4 and 10-3 M) or daidzein (10-7 to 10-5 M). The suppressive effect of genistein (10-5 M) was not further enhanced in the presence of calcitonin (10-8 M), DcAMP (10-5 M), or calcium chloride (10-3 M), and was completely abolished by the presence of dibucaine (10-6 M) or staurosporine (10-7 M), both of which are inhibitors of Ca2+-dependent protein kinases. Ca2+ ionophore (A23187; 10-6 M) induced a remarkable decrease in the number of osteoclasts in the absence or presence of genistein (10-5 M) or calcium chloride (10-3 M). The present study demonstrates that genistein has a direct suppressive effect on osteoclasts in vitro, suggesting that the isoflavone may induce apoptosis which is mediated through the pathway of intracellular Ca2+ signaling.
The immunomodulatory effects of allopurinol were investigated in a mouse contact hypersensitivity model. Allopurinol caused a time- and dose-dependent lethal effect in dinitrofluorobenzene (DNFB)-sensitized mice. Furthermore, allopurinol markedly uncreased ear swelling in the remaining mice. In contrast, TMX-67, a newly synthesized xanthine oxidase/xanthine dehydrogenase (XOD/XDH) inhibitor, had almost no effect on DNFB-sensitized mice. Allopurinol reduced both the spleen weitht and white blood cell count in DNFB-sensitized mice without affecting the T cell subset of splenocytes. The production of interferon (IFN)-γ, in the splenocytes of DNFB-sensitized mice was reduced by allopurinol administration. Death due to allopurinol was much lower in te non-sensitized mice than in the DNFB-sensitized mice. These findings indicate that allopurinol may interact with DNFB to enhance its toxicity and allopurinol might also modulate or enhance the inflammatory effect of DNFB. Also, DNFB may cause metabolic alterations via inflammation, leading to enhanced allopurinol toxicity.
To overcome the side effects of steroids, novel steroid-17-yl methyl glycolates with succinyl group at C-20, derived from predinisolone and dexamethasone were prepared based on concept of the antedrug. Their topical anti-inflammatory activity and systemic effects were evaluated trough croton oil-induced ear edema and paper disk granuloma bioassay. Among them, (20S)-succinyl dexamethasone derivatives (7 and 11) indicated more potent ati-inflammatory activity than the parent dexamethasone and did not show corticosteroidal side effects of thymic, adrenal involution or body weight loss. Both 7 and 11 were immediately metabolized into active compound 3 and this metabolite was eliminated with mean half-lives of 0.786 to 0.866 h in rat serum. Our findings suggest that these two compounds might be candidates as the novel steroids, and that that introduction of the succinyl group into the methyl glycolates at C-20 is useful to avoid suppressiion of organs due to the side effects of corticosteroids.
The prophylactic action of scymnol in a rat peripheral arterial occlusion model, involving injection of 5% lactic acid into the femoral artery, was investigated. Increases in serum lactate dehydrogenase (LDH), glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) activities and in plasma levels of thrombin and antithrombin III complex (TAT) were observed in this model 3 h after injection of lactic acid. Changes in LDH activity were characterized by increases in isozymes LDH4 and LDH5 and an elevated LDH4/LDH5 ratio. The ratio of the LDH4 to LDH5 increments was similar to that seen in a rat endothelial cell culture.Oral preadministration of scymnol had a preventive effect on the development of lesions in this model. It significantly reduced the LDH4 and LDH5 activity, the LDH4/LDH5 ratio and the TAT levels dose-dependently over the range 1, 3 or 10 mg/kg, compared with the values in control rats. However, its administration after lactic acid injection, or to sham-operated rats was ineffective, even at a dose of 10 mg/kg. The effects of scymnol were also compared with those of ticlopidine and argatroban.The findings show that scymnol may be useful in preventing thrombotic peripheral arterial occlusive disorders and that it potently protects endothelial cells against lactic acidosis in this model.
A series of naturally occurring bile alcohols, bile acids and their conjugates has been investigated as part of our studies to develop unique anticoagulants with a potent prophylactic effect against vascular endothelial cell injury induced by lactic acidosis in vivo and in vitro.In an in vivo rat peripheral arterial occlusion model induced by lactic acid injection, oral administration of a single dose of 3 mg/kg scymnol significantly inhibited edematous swelling and development of lower limb-lesions, including gangrene, and reduced changes in clotting system functions and serum lactate dehydrogenase activity. It had no effect on clotting system functions in sham-operated rats. The structure-activity relationship suggests that the [24R-(+)-5β-cholestane-3α, 7α, 24, 26-pentol] or [3α, 7α-dihydroxy-5β-cholanic acid] structure is important for a potent prophylactic effect following oral administration. Intraveous administration of a single dose of 0.3 mg/kg sodium (25S)-scymnol sulfate or scymnol prevented lesion progression as effectively as oral administration of scymnol. Sodium (25S)-scymnol sulfate and ursodeoxycholic acid showed clear protective effects against cultured vascular endothelial cell damage due to lactic acidosis which were dose-dependent.The above results suggest that bile steroids such as scymnol, sodium (25S)-scymnol sulfate, ursodeoxycholic acid, and chenodeoxycholic acid may play a role in protecting endothelial cells against injury caused by lactic acidosis. These compounds are candidates for novel anti-ischemic drugs that act by specifically protecting vascular endothelial cells.
To study whether we could enhance the liver targeting of DNA delivery via asialoglycoprotein receptors using a complex of poly-L-lysine (PLL)-condensed DNA galactosylated bovine serum albumin (GalBSA) (GPD complex), DNA was first combined with PLL and then with GalBSA via charge interaction (GalBSA : PLL : DNA=3 : 0.5 : 1, w/w/w). This vector was caracterized by dynamic laser light scattering, gel retardation assay, and electron microscopy to determine the particle size, electrostatic charge interaction, and 3-D structure. An electron micrography of GPD complex, where GalBSA : PLL : DNA=3 : 0.5 : 1 (w/w/w), showed a structure of spherical particles with a mean diameter of 145±24.2nm, and the complex was positively charged. The complex was tested for specificity and effeciency of gene transfer in cultured human hepatoblastoma cell line Hep G2 and mouse fibroblast cells NIH/3T3 in vitro. Cellular uptake was specifically dependent on the abundance of galactose recptors on target cells. Hep G2 cells transfected with GPD complexed with the fusogenic peptide KALA (WEAKLAKALAKALAKHLAKALAKALKACEA) showed a significantly higher reporter gene activity than those transfected with GPD comlex alone or free DNA-KALA complex. The efficiency of gene transfer mediated by GPD-KALA complex was not affected by the presece of serum in the transfection medium. The reporter gene activity in NIH/3T3 cells transfected with GPD complex was very low regardless of the presence of KALA and almost the same as that transfected with bovine serum albumin (BSA)-PLL-DNA complex (BPD complex). This gene transfer formulation may find potential applications for the gene therapy of liver diseases.
Bacitracin is an antibacterial cyclic dodecapeptide produced by Bacillus licheniformin. Besides antibacterial activity, it is reported to have a protease inhibitory activity and an absorption enhancing action. Here we determined the effects of bacitracin on transport of water-soluble dye fluoresceinisothiocyanate (FITC)-dextran across the rat intestinal mucosal membrane using an electrophysiological technique. Bacitracin enhanced the intestinal mucosal-to-serosal transport of FITC-dextran in concentration-dependent and pH-dependent manners. In particular, the addition of bacitracin to the mucosal side led to a remarkable enhancement of FITC-dextran transport across the colonic membrane. Furthermore, its exhibition of transport enhancement required the existence of metal divalent cations, Ca2+ and Mg2+, in the mucosal compartment. Electrophysiological study using voltageclamp technique revealed that a relatively lower concentration of bacitracin (5 mM) enhanced the transport of 6-carboxyfluorescein via a paracellular pathway in the colonic membrane and higher concentration of bacitracin (20 mM) affects both transcellular and paracellular routes, resulting in significant enhancement of 6-carboxyfluorescein across the colonic membrane. These findings might provide the useful information for enhancing the intestinal transport of poorly a sbsorbable drugs by bacitracin which has multiple functions.
We designed a new eukaryotic expression vector for secretable superoxide dismutase (SOD), which expresses human SOD cDNA by fusing it to 1 connecting amino acid and the signal peptide DNA sequence of the human interleukin-2 (IL-2) gane (IL-SOD(2) cDNA). The ILSOD(2) cDNA constructed by PCR-based gane expression was ligated into the multicloning site of the pRc/CMV plasmid (pRc/CMV-ILSOD(2)). Rat lung epithelial-like cells (L2 cells) and rat skin fibroblasts (FR cells) were transfected with pRc/CMV-ILSOD(2) by lipofection. The extracellular SOD activities of IS(2)-L2 cells (L2 cells transfected with pRc/CMV-ILSOD(2)) and IS(2)-FR cells (FR cells transfected with pRc/CMV-ILSOD(2)) were 2-3 times higher than those of host cells.Initially, we investigated the protective effect of extracellular SOD secreted from these transformed cells (IS(2)-L2 and IS(2)-FR cells) on extracellular superoxide anion (xanthine/xanthine oxidase; X/XO treatment)-induced cytotoxicity in normal cells. The sensitivities of these transformed cells to X/XO-induced cyottoxicity was decreased significantly as compared with that of host cells. Although, the conditioned medium from IS(2)-L2 and IS(2)-FR cells protected against X/XO-induced cytotoxicity, the conditioned medium from host cells (L2 and FR cells) showed no significant effects on X/XO-induced cytotoxicity. Furthermore, the conditioned medium from transformed cells was more effective than that of host cells against lipid peroxidation by normal cells under conditions of oxidative stress.Second, we generated superoxide anions in the intracellular space by paraquat treatment. The transformed cells were more sensitive to paraquat-induced cytotoxicity than host cells. Following addition of catalase, the sensitivity of these genetically modified cells to paraquat became aquivalent to that of host cells. These results indicated a protective effect of transfection with secretable SOD genes against extracellular superoxide anion-induced cytotoxicity although no such protective effect was observed against the intracellular cytotoxicity generated by paraquat treatment.
To estimate elastin metabolism in aneurysm, urinary levels of desmosine and elastin peptide in patients (n=23, range 54 to 85 years old) with aneurysm were measured by ELISA and compared between two control groups divided by age (<10 years old and >20 years old). The amounts of urinary desmosine and elastin peptide in the aneurysm group were significantly increased compared with those in the order control group (<20 years old). There was a correlation between urinary desmosine and elastin peptide in the young group. On the other hand, no such correlation was observed in the aneurysm group and the older control group. The distribution of the ratio (desmosine/elastin peptide) in the aneurysm group was different from that of the young control group. We conclude that assay of elastin peptide and desmosine in urine are useful in characterizing elastin degradation in a patient with aneurysm.
Notice of Retraction
The editorial committee has noticed that this publication as a Note in Biological and
Pharmaceutical Bulletin contains data sets identical to those presented in a paper, already
published in another journal, from the same laboratory with the same corresponding author.
Due to a violation of the editorial policies of the journal, this Note has been retracted by the
The Editorial Committee of the Pharmaceutical Society of Japan (April 15, 2014)
It is known that angiotensin II (Ang II) exerts an antifibrinolytic effect by stimulating synthesis of plasminogen activator inhibitor type-1 (PAI-1), a specific inhibitor of tissue plasminogen activator (t-PA). The aim of this study was to compare the antithrombotic potency of imidapril, an angiotensin-converting enzyme (ACE) inhibitor, and candesartan, an angiotensin II type 1 (AT1) receptor antagonist, in a model of arterial thromboss in spontaneously hypertensive rats (SHRs).Oral treatment with 5 mg/kg imidapril 1 h before induction of thrombosis resulted in a significant reduction in thrombus weight, whereas candesartan did not affect thrombus weight the same treatment conditions. Candesartan lowered blood pressure to the same degree as in the imidapril-treated rats. Imidapril not only reduce the serum and aortic ACE activities, but also reduced aortic PAI-1 protein levels, while candesartan had no effect on theses.These results suggest that imidapril, but not the AT1 receptor antagonist, candesartan, enhances fibrinolysis via a reduction of aortic PAI-1 levels by inhibiting ACE and prevents thrombus formation in SHRs.
This paper reports that β-N-acetylglucosaminidase from bovine lens has potent enzyme activity compared with other glycosidases in the lens. The partially purified enzyme was used to determine its physiological properties. The optimal pH and optimal temperature of this enzyme was approximately 6.3 and 40°C, respectively. The apparent native molecular weight of this enzyme obtained by gel filtration chromatography was 540 kDa. Furthermore, the enzyme fraction contained 3 polypeptides with molecular weights of 28.8, 28.0 and 26.0 kDa, although it is not certain it they were one of the components of this enzyme in the current study. The Km value of this enzyme was 92.3 μM and it was inhibited strongly by HgCl2 and sodium dodecyl sulfate (SDS).
We examined the antiallergic effects of phyllodulcin, hydrangenol, and their 8-O-glucosides, and thunberginols A and F isolated from the processed leaves (Hydrangeae Dulcis Folium) and dried leaves of Hydrangea macrophylla SERINGE var. thunbergii MAKINO using the passive cutaneous anaphylaxis (PCA) reaction. With the exception of phyllodulcin, these constituents were found to significantly inhibit the PCA reaction. Although thunberginol A showed the most potent inhibitory effect, hydrangenol was considered to be the principal antiallergic component in the processed leaves, after taking into account their contents.
We previously reported the isolation of a novel cerebroside (1-O-(β-D-glucopyranosyl)-(2S, 3R, 4E, 8Z)-2-N-palmityloctadecasphinga-4, 8-diene; LCC) from the fruits of Lycium chinense MILL. (Solanaceae) which protected primary cultured rat hepatocytes from the toxicity induced by carbon tetrachloride (CCl4). The present study was conducted to determine the mechanism(s) by which LCC might exert its hepatoprotective activity. To determine the effect of LCC on the glutathione (GSH) redox system, we measured the activities of enzymes involved in the system as well as the levels of hepatic mitochondrial GSH and malondiadehyde (MDA). The hepatotoxicant, CCl4 routinely decreased levels of total and reduced GSH. The levels of these compounds were significantly maintained at the levels of the control cultures following treatment with LCC. The decreased activities of glutathione reductase and glutathione peroxidase in CCl4-injured rat hepatocytes were significantly increased by the treatment of LCC. Furthermore, the elevated levels of MDA seen in CCl4-injured rat hepatocytes were reduced after treatment with LCC in a concentration dependent manner over a range of 1-10 μM. From these results, we postulate that LCC may preserve the hepatic mitochondrial level of GSH by scavenging reactive oxygen species produced during CCl4-induced toxicity and thereby reduce lipid peroxidation and cellular damage.
Transport and recognition of aminopeptidase-resistant cellobiose-coupled tyrosylglycylglycine (CcpTGG) by intestinal Na+/glucose cotransporter (SGLT1) was examined in rat small intestine. Inhibitory effect of phloridzin (SGLT1 inhibitor) on the CcpTGG transport was extremely low. Concentration dependence of the CcpTGG transport was observed, but the primary component of transport was pasisve diffusion However, CcpTGG significantly inhibited SGLT1-mediated transport, indicating its recognition by SGLT1. Other glucose-conjugates also inhibited SGLT1-mediated transport. These results indicate that recognition of sugar conjugates by SGLT1 is much less restricted than transport, and that it should be relatively easier to design SGLT1 inhibitors than SGLT1-transportable sugar conjugates.
The present study provides the evidence that dieldrin is reductively metabolized to aldrin by intestinal bacteria in rats. When dieldrin was incubated with the cecal contents of rats, aldrin, a reduced metabolite of the epoxide, was isolated from the incubation mixture. The metabolite was identified unequivocally by UV and mass spectral comparison with an authentic sample, and on the basis of its TLC and HPLC behavior. The cecal contents of rats exhibited epoxide reductase activity toward dieldrin under anaerobic conditions. However, only marginal activity was observed under aerobic conditions. Four purestrains of intestinal bacteria exhibited epoxide reductase activities to varying degrees under anaerobic conditions. The highest activity was observed in Clostridium sporogenes. Cell-free extracts of the intestinal becteria in rat cecal contents showed reductase activity when supplemented with both NAD(P)H and FMN under anaerobic conditions.
The present study provides the evidence that DT-diaphorase-like quinone reductase exists in rat plasma. The quinone reductase activity toward menadione was found in rat plasma in the presence of NADH or NADPH. The enzyme activity was induced by pretreatment with 3-methylcholanthrene, but was not affected by phenobarbital. The 3-methylcholanthrene-induced quinone reductase activity was separated into three fractions (F1, F2, and F3) by gel filtration, which showed NAD(P)H-linked, NADH-linked, and NAD(P)H-linked activities, respectively. F1, which was induced by 3-methylcholanthrene, was inhibited by dicumarol, and cross-reacted with rat liver DT-diaphorase antibody.
We recently found that guinea pig gastric pit cells in culture undergo spontaneous and rapid apoptotic DNA fragmentation, which may represent the rapid death of gastric pit cells in vivo. In this study, we observed that pretreatment of cells with geranylgeranylacetone, an antiulcer drug with heat-shock protein-inducing activity, suppressed the spontaneous apoptotic DNA fragmentation in a dose-dependent manner. Pretreatment of cells with low concentrations of ethanol or heat-shock also prevented the spontaneous apoptotic DNA fragmentation. These observations indicate that the suppression of the apoptotic DNA fragmentation by geranylgeranylacetone involve the induction of heat-shock proteins.