Biomedical subjects

E Nakashima

Publications and source records attributed to E Nakashima.

At least 55 records · Page 3Linked to original sources

PubMed1998

Characteristic subcellular distribution, in brain, heart and lung, of biperiden, trihexyphenidyl, and (-)-quinuclidinyl benzylate in rats.

The subcellular distribution of biperiden (BP), trihexyphenidyl (TP) and (-)-quinuclidinyl benzylate (QNB) in brain, heart and lung following high dose (3.2 mg/kg) i.v. administration was investigated in rats. The subcellular distribution of BP or TP used clinically conformed with that of QNB, a typical potent central muscarinic antagonist. The concentration-time courses of the brain subcellular fractions for these drugs were of two types which decreased slowly and in parallel to the plasma concentration. The subcellular distribution in the brain and heart was dependent on the protein amount of each fraction. The percent post-nuclear fraction (P2) of the total concentration in the lung was characteristically about 3-5 times larger than that in the heart. It was elucidated that the distribution in the lung differs from that in the brain and heart, with high affinity which is not dependent on the protein amount in the P2 fraction containing lysosomes. On the other hand, at a low dose (650 ng/kg) of 3H-QNB, each fraction as a percentage of the total concentration in the brain increased in synaptic membrane and synaptic vesicles and decreased in nuclei and cytosol as compared with the high dose. These results show that although the tissue concentration-time courses of anticholinergic drugs appear to decrease simply in parallel to plasma concentration, the subcellular distribution exhibits a variety of patterns among various tissues.

Animals↗

PubMed1998

Uptake of basic drugs into rat lung granule fraction in vitro.

Although basic drugs are distributed widely in various tissues, they are characteristically concentrated in the lung granule fraction. We examined the uptake of seven lipophilic basic drugs into rat lung granule fraction (P2) in vitro and investigated the contributions of drug lipophilicity and lysosomal trapping to the characteristic lung P2 distribution. The uptake of each drug into P2 was examined at various pH values. The drug concentration in P2 was determined by gas chromatography. Biperiden (BP) was rapidly taken up into P2, reaching a maximal concentration within 1 min at pH 7.4 at both 4 degrees C and 37 degrees C. Both BP and chlorpromazine uptake into P2 was biphasic. Though the uptake rates of the seven drugs into P2 increased with rising pH, the rate of increase varied for each drug. There was a good correlation between the octanol-water partition coefficient of the non-ionized form (P(oct)) of each drug and the uptake into P2 in the presence or absence of NH4Cl, which inhibits lysosomal trapping. However, uptake into P2 in the presence of NH4Cl showed a stronger P(oct)-dependency. We conclude that the distribution of basic drugs into lung P2 is dependent on both drug lipophilicity and lysosomal uptake.

Ammonium Chloride↗

PubMed1998

Flow cytometry measurements of subsets of T, B and NK cells in peripheral blood lymphocytes of atomic bomb survivors.

Previous studies of blood cells from atomic bomb survivors have shown that frequencies of chromosome aberrations and somatic mutations are elevated in heavily exposed survivors and that T-cell functions and the number of mature T cells are decreased in the survivors who were exposed to radiation as adults. Current progress in flow cytometry allows a sophisticated analysis of various subsets of T, B and NK cells. In the present study, proportions of such subsets in peripheral blood lymphocytes from atomic bomb survivors (159 survivors estimated to be exposed to > or =1.5 Gy) and 252 controls were measured using multiple combinations of monoclonal antibodies to lymphocyte differentiation antigens to investigate whether the previous radiation exposure had altered the composition of the subsets. Among T-cell subsets, the proportion of CD4+ T-cell subsets was decreased significantly in the heavily exposed survivors; this tendency was apparent for the CD4+CD45RA+ naive T-cell subset. However, there were no significant differences in the proportions of CD8+ T-cell subsets between the exposed survivors and controls. As for the B-cell subsets, the proportion of both CD5+ and CD5 B cells as well as CD23+ and CD23- B cells increased in the heavily exposed survivors. Further, no effect of radiation was found in the proportion of NK-cell subsets. These results strongly suggest that previous radiation exposure altered the composition of T and B cells in the peripheral blood of atomic bomb survivors, and they raise the possibility that atomic bomb radiation may have affected the developmental processes of T and B cells.

Adult↗

PubMed1998

Polyol pathway hyperactivity is closely related to carnitine deficiency in the pathogenesis of diabetic neuropathy of streptozotocin-diabetic rats.

To investigate the relationship between polyol pathway hyperactivity and altered carnitine metabolism in the pathogenesis of diabetic neuropathy, the effects of an aldose reductase inhibitor, [5-(3-thienyl) tetrazol-1-yl]acetic acid (TAT), and a carnitine analog, acetyl-L-carnitine (ALC), on neural functions and biochemistry and hemodynamic factors were compared in streptozotocin-diabetic rats. Significantly delayed motor nerve conduction velocity, decreased R-R interval variation, reduced sciatic nerve blood flow and decreased erythrocyte 2, 3-diphosphoglycerate concentrations in diabetic rats were all ameliorated by treatment with TAT (administered with rat chow containing 0.05% TAT, approximately 50 mg/kg/day) or ALC (by gavage, 300 mg/kg/day) for 4 weeks. Platelet hyperaggregation activity in diabetic rats was diminished by TAT but not by ALC. TAT decreased sorbitol accumulation and prevented not only myo-inositol depletion but also free-carnitine deficiency in diabetic nerves. On the other hand, ALC also increased the myo-inositol as well as the free-carnitine content without affecting the sorbitol content. These observations suggest that there is a close relationship between increased polyol pathway activity and carnitine deficiency in the development of diabetic neuropathy and that an aldose reductase inhibitor, TAT, and a carnitine analog, ALC, have therapeutic potential for the treatment of diabetic neuropathy.

Acetylcarnitine↗

PubMed1997

Molecular cloning of a gene encoding a new type of metalloproteinase-disintegrin family protein with thrombospondin motifs as an inflammation associated gene.

A cellular disintegrin and metalloproteinase (ADAM) is a new family of genes with structural homology to the snake venom metalloproteinases and disintegrins. We screened genes which were selectively expressed in the cachexigenic colon 26 adenocarcinoma subline in vivo. It was found that one novel cDNA clone, identified as a cachexigenic tumor selective gene, encodes a cysteine-rich protein which shows a sequence similarity to that of both the snake venom metalloproteinases and thrombospondins. We named this cDNA clone A disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS-1). ADAMTS1 consists of six domains, 1) a pro- and 2) a metalloproteinase, 3) a disintegrin-like, 4) a thrombospondin (TSP) homologous domain containing TSP type I motif, 5) a spacer region, and 6) COOH-terminal TSP submotifs. Unlike other ADAMs, ADAMTS-1 does not possess a transmembrane domain and is a putative secretory protein. Therefore, ADAMTS-1 is a new type of ADAM family protein with TSP type I motifs. We demonstrated that the TSP homologous domain containing the TSP type I motif of ADAMTS-1 is functional for binding to heparin. ADAMTS-1 mRNA could be induced by stimulating colon 26 cells with an inflammatory cytokine, interleukin-1, in vitro. Moreover, intravenous administration of lipopolysaccharide in mice selectively induced ADAMTS-1 mRNA in kidney and heart. These data suggest that ADAM-TS-1 may be a gene whose expression is associated with various inflammatory processes as well as development of cancer cachexia.

ADAM Proteins↗

PubMed1997

Long-term evolution of fibrosis from chronic hepatitis to cirrhosis in patients with hepatitis C: morphometric analysis of repeated biopsies.

To clarify the characteristics of fibrosis developed in the process from chronic hepatitis C to cirrhosis, a morphometric analysis of liver biopsy samples was conducted on 25 chronic hepatitis C patients and 20 chronic hepatitis B patients (controls). Hepatitis C patients were followed up for 3 to 23 years. The mean number of liver biopsies performed on these patients was 3.8. Each biopsy was evaluated for the degree of fibrosis by using two methods: a semiquantitative method with a staging scoring system, and morphometry using a computed image analysis system. A significant correlation was observed between the Stage and the area of fibrosis (AF = the ratio of the area of fibrosis to that of the entire tissue specimen). The AF in cirrhosis was significantly higher in hepatitis C patients than in hepatitis B patients. The ratio of AF in the last biopsy sample to AF in the initial biopsy sample was significantly higher in hepatitis C patients than in hepatitis B patients. Evolution from chronic hepatitis C to cirrhosis occurred more frequently in patients aged > or = 50 years, and this time period was 1.8 times shorter than that in patients aged < 50 years. AF in the initial biopsy related significantly to the period of evolution from chronic hepatitis C to cirrhosis. AF in the initial biopsy might be a predictive factor for prognosis.

Adult↗

PubMed1997

Pathology of chronic hepatitis C in children. Child Liver Study Group of Japan.

Limited information is available regarding the histology of hepatitis C virus infection in children. The aim of this study was to determine the histological pattern of chronic hepatitis C (CHC) in children, and liver biopsy specimens from 109 pediatric patients with CHC were examined. Each biopsy specimen was evaluated based on a numerical scoring system for the stage of fibrosis (1-4), the grade of portal/periportal necroinflammation (0-4), the grade of lobular necroinflammation (0-4), and their sum (final grade). The histological lesions considered to be characteristic of chronic hepatitis were also evaluated. None of the children had liver cirrhosis, and 105 cases (97%) were stage 1 or 2. Only 4 children were stage 3. Two of these 4 cases showed hemosiderosis. A significant correlation was observed between the staging score and the final grade in the pediatric patients (r = .59; P < .0001). The histological characteristics of adult CHC, such as lymphoid aggregate, bile duct injury, and fatty changes, were also observed in the children. In conclusion, the majority of children with CHC presented with mild fibrosis, but a few showed CHC with lobular distortion and hemosiderosis. Frequent blood transfusion may aggravate hepatic lesions in pediatric CHC.

Adolescent↗

PubMed1997

Diabetic neuropathy in sucrose-fed Otsuka Long-Evans Tokushima fatty rats: effect of an aldose reductase inhibitor, TAT.

In an animal model of human non-insulin dependent diabetes mellitus (NIDDM), Otsuka Long-Evans Tokushima Fatty (OLETF) rats were fed with sucrose for 8 weeks to obtain severe hyperglycemia. The effects of sucrose administration on peripheral nerve functions, motor nerve conduction velocity (MNCV) and coefficient of variance of R-R interval (CVR-R), were investigated with concomitant measuring of sciatic nerve blood flow (SNBF), ADP-induced platelet aggregation and polyol content in the sciatic nerves. The effects of an aldose reductase inhibitor, TAT, on these parameters were also studied. Administration of sucrose to OLETF rats caused significant body weight reduction and remarkable hyperglycemia. Sucrose-fed OLETF rats demonstrated significantly delayed MNCV, decreased CVR-R, reduced SNBF and increased platelet aggregation activity to ADP. Sorbitol and fructose accumulation, and myo-inositol depletion in sciatic nerves were observed only in sucrose-fed OLETF rats. These abnormalities were all ameliorated by the treatment with TAT. These observations suggest that the sucrose-fed OLETF rat is a useful animal model for studying the pathogenesis of diabetic neuropathy in human NIDDM, and that an aldose reductase inhibitor is a useful therapeutic agent for the treatment of diabetic neuropathy.

Aldehyde Reductase↗

PubMed1997

Hepatitis C virus RNA present in saliva but absent in breast-milk of the hepatitis C carrier mother.

In order to examine whether saliva and breast-milk are mediators of the vertical transmission of hepatitis C virus (HCV) from an HCV carrier mother, serum, saliva, and breast-milk samples from 11 HCV carrier mothers were collected at the time of delivery, and at approximately 1- to 3-months intervals for as long as 30 months postpartum. Serum was also sampled from their children. All samples were analysed for the presence of HCV RNA, using the nested polymerase chain reaction method. No HCV RNA was detected in any breast-milk samples. In saliva, HCV RNA was detected in four of the 11 mothers (36%). These four mothers also had liver function abnormalities. Hepatitis C virus RNA was not detected in any serum samples of the children, and all children had normal liver function. The children were monitored for periods from 2 to 44 months. During this period, there was no evidence of virus transmission. Breast-milk is not likely to be a source of mother-to-child transmission of HCV. Maternal saliva may harbour HCV, but it may not result in infant infection.

Child, Preschool↗

PubMed1997

Prediction of changes in the clinical pharmacokinetics of basic drugs on the basis of octanol-water partition coefficients.

A physiologically based pharmacokinetic model for basic drugs has been established on the basis of octanol-water partition coefficients of the non-ionized, unbound drugs (Poct). The parameters for the physiological model in man were estimated from a regression equation obtained for the relationships between the Poct and the tissue-plasma partition coefficient, the hepatic intrinsic clearance (CLint,h) and the blood-to-plasma concentration ratio in rabbits. The plasma concentrations observed after intravenous administration of ten basic drugs (3.2 mg kg-1) to rabbits agreed with the levels predicted using the physiological model (r = 0.710-0.980). In man, the predicted plasma concentrations of basic drugs were in good agreement with reported values (r = 0.729-0.973), except for diazepam and pentazocine. Variations in plasma and brain-concentration profiles of clomipramine and nitrazepam in various disease states were simulated using the model. We assumed that the changes in unbound fraction of drug in serum (fp), CLint,h and the hepatic blood flow rate were from 0.25- to 4-fold that of the control and that fat volume changed by 0.2- to 5-fold. With regard to changes in fp, we predicted that the brain-plasma concentration ratio of clomipramine was 1.5- to 25-fold that of the control 24 h after intravenous administration, although the variations in the plasma concentration-time profiles were less marked. Plasma concentrations predicted for several basic drugs were in good agreement with reported values and this physiological model could be useful for predicting drug-disposition kinetics in man.

Animals↗

PubMed1997

Relationships between the hepatic intrinsic clearance or blood cell-plasma partition coefficient in the rabbit and the lipophilicity of basic drugs.

The relationships between drug lipophilicity and hepatic intrinsic clearance (CLint,h) or red blood cell-plasma partition coefficients (D) have been elucidated for ten highly lipophilic basic drugs with apparent octanol-water partition coefficients at pH 7.4 (Papp,oct) or 150 or above. The true octanol-water partition coefficients of the non-ionized drugs (Poct) were used to determine CLint,h and D for the unbound drugs (CLint,h,f and Df, respectively), and CLint,h,f and Df for the non-ionized and unbound drugs (CLint,h fu and Dfu, respectively). The total clearance values were determined at steady state by infusion studies of individual drugs in rabbits. There was better correlation between log Poct and log CLint,h,fu (r = 0.974) than between log Poct and log CLint,h,f (r = 0.864). The D values were calculated from the blood-plasma concentration ratio. There was a better correlation between log Poct and log Dfu (r = 0.944) than between log Poct and log Df (r = 0.612). The regression equations obtained were CLint,h,fu = 0.0875 x Poct1.338 and Dfu = 0.0108 x Poct0.970, respectively. These results show that the CLint,h and D of highly lipophilic basic drugs can be predicted from Poct by taking fu into consideration. By applying these parameters to a physiologically based pharmacokinetic model it might be possible to predict the pharmacokinetics of unknown basic drugs.

Animals↗

PubMed1997

Electroretinogram in sucrose-fed diabetic rats treated with an aldose reductase inhibitor or an anticoagulant.

To investigate the role of increased polyol pathway activity and hemodynamic deficits in the pathogenesis of diabetic retinopathy in non-insulin-dependent diabetes mellitus (NIDDM), Otsuka Long-Evans Tokushima fatty (OLETF) rats, an animal model of human NIDDM, were given water with or without 30% sucrose and some of them were fed laboratory chow containing 0.03% cilostazol, an anticoagulant, or 0.05% [5-(3-thienyl)tetrazol-1-yl] acetic acid monohydrate (TAT), an aldose reductase inhibitor, for 8 wk. Long-Evans Tokushima Otsuka (LETO) rats were used as nondiabetic controls. The peak latencies of oscillatory potentials of the electroretinogram in sucrose-fed OLETF rats were significantly prolonged compared with those in OLETF rats without sucrose feeding and LETO rats. There was a marked increase in platelet aggregability and a significant decrease in erythrocyte 2,3-diphosphoglycerate in sucrose-fed OLETF rats. Cilostazol significantly improved these parameters without changes in retinal levels of sorbitol and fructose. TAT, however, ameliorated all of these parameters. These findings confirm that the sucrose-fed OLETF rat is a useful animal model of retinopathy in human NIDDM and suggest that cilostazol improved diabetic retinopathy by modifying vascular factors, not by altering polyol pathway activity.

2,3-Diphosphoglycerate↗

PubMed1997

Effects of glycemic control on plasma 3-deoxyglucosone levels in NIDDM patients.

OBJECTIVE: To clarify the effects of glycemic control on the level of 3-deoxyglucosone (3-DG), a reactive dicarbonyl compound, in plasma from diabetic patients. RESEARCH DESIGN AND METHODS: Fasting plasma samples were collected from 15 healthy volunteers and 27 patients with NIDDM. Samples were collected from six poorly controlled patients before and after improved glycemic control for at least 2 months. Plasma 3-DG was determined by high-performance liquid chromatography (HPLC) as a 2,3-diaminonaphthalene derivative. We observed the relationship of 3-DG levels with plasma glucose or HbA1c levels and examined changes in 3-DG levels after glycemic control in the six patients. RESULTS: Plasma 3-DG was significantly more increased in diabetic patients than in nondiabetic control subjects (31.8 +/- 11.3 vs. 12.8 +/- 5.2 ng/ml, means +/- SD, P < 0.001), but there was an approximately threefold difference in 3-DG levels among diabetic patients. 3-DG levels were well correlated with plasma glucose (r = 0.56, P < 0.005) and HbA1c levels (r = 0.74, P < 0.001) in diabetic patients. The improvement of hyperglycemia in six patients resulted in a significant decrease in 3-DG (35.2 +/- 13.2 vs. 21.3 +/- 3.4 ng/ml, P < 0.05). CONCLUSIONS: The results indicate that the plasma glucose level is a predominant determinant of the plasma 3-DG level in diabetic patients and good glycemic control would be important to reduce this reactive metabolite.

Adult↗

PubMed1997

Increased alanine uptake and lipid synthesis from alanine in isolated hepatocytes of Wistar-Kyoto fatty rats: an inhibitory effect of biguanides.

To examine the pathophysiological characteristics of non-insulin-dependent diabetes mellitus, alanine metabolism in isolated hepatocytes of male Wistar-Kyoto (WKY) fatty rats (genetically obese and hyperglycemic) and their lean littermates was investigated. The effects of glucagon and the biguanides, metformin and buformin, on alanine metabolism were also studied by measuring alanine uptake and lipid synthesis from alanine. WKY fatty rats showed higher plasma insulin and lipid concentrations than lean rats at 5 as well as at 12 weeks of age. Alanine uptake into hepatocytes was increased in fatty rats only at 12 weeks of age compared with lean rats. Lipid synthesis from alanine in hepatocytes was increased in fatty rats at 5 and 12 weeks of age compared with lean rats. Glucagon increased alanine uptake into hepatocytes but did not affect lipid synthesis from alanine in both fatty and lean rats. Low concentrations (0.1 mM) of biguanides decreased lipid synthesis from alanine only in fatty rats without inhibiting alanine uptake into hepatocytes. These observations suggest that lipid synthesis from alanine in hepatocytes of WKY fatty rats is accelerated prior to the onset of diabetes mellitus, which might be associated with the development of diabetes, and that an inhibitory effect on increased lipid synthesis is one of the pharmacodynamic actions of biguanides.

Aging↗

PubMed1996

Correlation between systolic blood pressure and physical development in adolescence.

Although the close relation between blood pressure and physical development in adolescence has been established in cross-sectional and comparative cross-sectional studies, the entire trend of systolic blood pressure (SBP) during adolescence has not been elucidated in conjunction with physical development in a longitudinal study. Blood pressure (mmHg), body weight (kg), and body height (m) were measured annually for 418 subjects in Hiroshima and Nagasaki, Japan, from age 10 (1955 or 1956) through 18 years (1963 or 1964). The Gompertz growth model was used to determine the velocity of weight increase (VEL) during that age period. The relations between SBP from age 10 to 18 and VEL, weight, height, body mass index (BMI; weight/height2, kg/m2), and the age at which the measurements were made were investigated individually using random-coefficient growth-curve analysis. The SBP trend for the 10- to 18-year age period could be shown by the following prediction equations: for the 163 Hiroshima males, SBP = 82.38 + 0.89 VEL at age 1.15 years prior to the current examination (VEL (age - 1.15)) + 1.40 BMI; for the 57 Nagasaki males, SBP = 92.70 + 1.07 VEL (age - 1.15) + 0.79 BMI; for the 148 Hiroshima females, SBP = 104.88 + 1.63 VEL (age - 1.15) + 0.05 BMI; for the 50 Nagasaki females, SBP = 113.62 + 1.67 VEL (age - 1.15) - 0.59 BMI. VEL 1.15 years prior to the current examination was significantly and positively related to SBP in each city by sex group (p < 0.01), and current BMI was significantly related to SBP for males in Hiroshima (p < 0.01) and nearly so in Nagasaki (p = 0.06), but not for females in either city (p = 0.84 and 0.13, respectively). Because the plot of VEL was a convex curve, SBP peaked approximately 1-2 years after the peak in VEL and then decreased in both sexes. The entire SBP trend during adolescence can be expressed as an equation of VEL and BMI in males and of VEL in females. SBP does not increase linearly with age.

Adolescent↗

PubMed1996

Effects of menopause on trends of serum cholesterol, blood pressure, and body mass index.

BACKGROUND: To elucidate the impact of menopause on coronary risk factors, we determined the trends of serum cholesterol (mg/dL), blood pressure (BP, mm Hg), and body mass index (BMI, kg/m2) and investigated whether menopause affects these trends in women in Nagasaki, Japan. METHODS AND RESULTS: Trends of cholesterol, systolic BP (SBP), and BMI from 9 years before menopause through 9 years after menopause in 579 women with natural menopause (ranging in age from 40.2+/-3.1 to 57.9+/-3.1 years; age at menopause, 49.4+/-3.0 years) and 134 women with surgical menopause (hysterectomy with or without bilateral oophorectomy; ranging in age from 34.9+/-4.5 to 51.7+/-5.1 years; age at menopause, 42.9+/-5.0 years) and those in 579 and 134 age- and time-matched male subjects (ranging in age from 40.1+/-3.1 to 57.8+/-3.2 years and from 35.2+/-4.5 to 51.6+/-5.0 years, respectively) in Nagasaki were determined by rearrangement of the data from 1958 to 1989 with time of menopause as the datum line. Although cholesterol tended to increase with age in both sexes, it increased significantly in women from 3 years before natural menopause to 1 year after natural menopause and from 1 year before surgical menopause to 1 year after surgical menopause. SBP and BMI did not exhibit a significant increase in relation to natural or surgical menopause. In male subjects, no significant increase of cholesterol, SBP, or BMI was observed at the age corresponding to natural or surgical menopause. CONCLUSIONS: Natural menopause and surgical menopause exert an effect only on cholesterol, and an increase in cholesterol precedes natural menopause by 3 years and occurs at the time of surgical menopause.

Adult↗

PubMed1996

Effects of propionyl-L-carnitine and insulin on the electroretinogram, nerve conduction and nerve blood flow in rats with streptozotocin-induced diabetes.

The effect of an analogue of L-carnitine, propionyl-L-carnitine, on the electroretinogram, motor nerve conduction velocity and nerve blood flow was determined in rats with streptozotocin-induced diabetes, and was compared with the effects of insulin alone or combined therapy. Oral administration of propionyl-L-carnitine (3 g/kg daily for 4 weeks) significantly increased caudal nerve motor conduction velocity and sciatic nerve blood flow in diabetic rats. There were no differences in the effects of insulin (8-10 U daily for 4 weeks), propionyl-L-carnitine and combined therapy. Although propionyl-L-carnitine significantly shortened the peak latency of the electroretinogram b-wave in diabetic rats, its effect was far weaker than that of insulin or combined therapy, with combined therapy producing the greatest improvement. These effects of propionyl-L-carnitine were accompanied by a decrease of serum lipid levels, an increase of the sciatic nerve carnitine content, and no changes of the tissue (nerve and retinal) sorbitol and myo-inositol concentrations. In contrast, insulin significantly reduced the tissue sorbitol content and markedly increased myo-inositol. These findings suggest that propionyl-L-carnitine may improve diabetic neuropathy and retinopathy without influencing the polyol pathway, and that this beneficial effect may be mediated through the amelioration of microcirculation and tissue carnitine content, thus probably increasing fatty acid oxidation.

Animals↗

PubMed1996

Effect of a novel hypoglycemic agent, KAD-1229 on glucose metabolism and fructose-2,6-bisphosphate content in isolated hepatocytes of normal rats.

The effects of a novel hypoglycemic agent, calcium(2s)-2-benzyl-3-(cis-hexahydro-2-isoindolinylcarbonyl) propionate dihydrate (KAD-1229), which is a benzyl succinate derivative, on liver metabolism were investigated using isolated hepatocytes from normal rats. In the presence of 10 mM glucose, KAD-1229 increased the L-lactate production (41.1 +/- 0.9 versus 60.9 +/- 2.6 mumol of lactate/g of cells/30 min; P < 0.05) and inhibited gluconeogenesis in hepatocytes (0.94 +/- 0.02 versus 0.70 +/- 0.03 mumol of [2-14C]-pyruvate converted to glucose/g of cells/20 min; P < 0.05). These effects by KAD-1229 were accompanied by an increase in the cellular content of fructose-2,6-bisphosphate (F-2,6-P2), which is one of the important regulators of hepatic glucose metabolism, in a dose-dependent manner (0.05-2.5 mM). KAD-1229 also stimulated the oxidation of [2-14C]-pyruvate and [6-14C]-glucose in the tricarboxylic acid cycle (+18 and +31%, respectively), indicating that stimulation of tricarboxylic acid cycle activity and/or enhancement of the glycolytic flux rate had occurred. Moreover, KAD-1229 did not modify the activities of 6-phosphofructo 2-kinase or fructose-2,6-bisphosphatase, but increased significantly the accumulation of fructose 6-phosphate in hepatocytes. These results suggest that KAD-1229 has extrapancreatic effects on hepatic glucose metabolism, that its actions are mediated through the inhibition of fructose-1,6-bisphosphatase and stimulation of both the 6-phosphofructo 1-kinase reaction and tricarboxylic acid cycle activity by increasing the F-2,6-P2 content in hepatocytes, and that these multiple effects may account in part for the ability of KAD-1229 to reduce blood glucose levels in vivo.

Analysis of Variance↗