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Biomedical subjects

E Hayashi

Publications and source records attributed to E Hayashi.

At least 109 records · Page 6Linked to original sources
PubMed1984

Enhancement in cholesterol-esterase activity and lipolysis due to 17 beta-estradiol treatment in rat adipose tissue.

The effects of 17 beta-estradiol and testosterone administration on cholesterol esterase, lipoprotein lipase activities and adrenalin-induced lipolysis were examined in rat adipose tissues with the change in serum lipid level. The administration of 17 beta-estradiol (500 micrograms/kg, 2 or 4 weeks) to male rats significantly reduced the body weight, and markedly increased serum cholesterol, triacylglycerols and phospholipids. Cholesterol esterase activity was significantly enhanced in the epididymal adipose tissue from estradiol treated rats and the effect was greater with duration of the treatment. In contrast, lipoprotein lipase activity was markedly reduced. Testosterone reduced cholesterol esterase activity in the parametrial adipose tissue through the treatment with 500 micrograms/kg for 6 weeks, but it did neither influence serum lipids nor lipoprotein lipase activity. Basal lipolysis and adrenalin-induced lipolysis were also significantly enhanced in the epididymal adipose tissue from the male rat treated either with 7 mg/kg estradiol 12 h ahead or with 500 micrograms/kg estradiol for 2 weeks. These results indicate that estradiol exerts strong effects on metabolism of the adipose and these effects seems to be mediated through cyclic-AMP. An alteration of adrenergic functions by gonadal steroids might be intervened.

Adipose Tissue↗
PubMed1984

Neosurugatoxin, a specific antagonist of nicotinic acetylcholine receptors.

Neosurugatoxin (NSTX) (3 nM-30 nM), recently isolated from the Japanese ivory mollusc (Babylonia japonica) exerted a potent antinicotinic action in the isolated guinea pig ileum. Specific [3H]nicotine binding to rat forebrain membranes was saturable, reversible, and of high affinity. Nicotinic cholinergic agonists exhibited a markedly greater affinity for [3H]nicotine binding sites than a muscarinic agonist, oxotremorine. Although alpha-bungarotoxin had no effect on [3H]nicotine binding, low concentrations (1 nM-1 microM) of NSTX inhibited [3H]nicotine binding in the forebrain membranes and its IC50 value was 69 +/- 6 nM. On the other hand, NSTX did not affect muscarinic receptor binding in the brain. These data indicate that NSTX may be of appreciable interest as a neurotoxin with a selective affinity for ganglionic nicotinic receptors.

Animals↗
PubMed1984

Inhibition by chlorpromazine, metals and I-ascorbic acid of calcium-ATPase and magnesium-ATPase in bovine adrenal medullary microsomes.

Effects of chlorpromazine, metals and I-ascorbic acid (AA) on Ca2+-ATPase and Mg2+-ATPase in microsomal and granular fractions obtained from the bovine adrenal medulla were studied. Marker enzyme analysis on microsomal subfractions in a discontinuous sucrose density gradient showed a correlation of distribution between ATPase activities and plasma membrane. The two ATPase activities in such plasma membrane-rich microsomes were reduced by chlorpromazine, Hg2+ and Cu2+ (0.3 mM of each), and their effects were greater on the Mg2+-ATPase activity. Zn2+ (0.3 mM) also reduced only the Mg2+-ATPase activity. AA (3 mM) reduced the two ATPase activities to an equal extent. Nevertheless, the inhibitions of ATPases by Hg2+, Cu2+ and Zn2+ were decreased, unaltered and additively enhanced in combination with AA, respectively. We also observed high Mg2+-ATPase activity in the granule-rich fraction, but this ATPase activity was unaffected by all of the above agents. These results indicate that Mg2+-ATPase in the plasma membrane-rich microsome of adrenal medulla is inhibited by chlorpromazine, Hg2+, Cu2+ and Zn2+ more significantly than Ca2+-ATPase, but Mg2+-ATPase in the granular fraction is unaffected, and that AA changes the potency of inhibition by some metals of ATPases diversely.

Adenosine Triphosphatases↗
PubMed1984

Alterations in cardiac alpha and beta adrenoceptors during the development of spontaneous hypertension.

To study potential cardiac receptor alterations during the development of spontaneous hypertension, specific binding of [3H]-2-N(2,6-dimethoxyphenoxyethyl)amino-methyl-1,4-benzodioxane, (-)-[3H]dihydroalprenolol and (-)-[3H]quinuclidinyl benzilate in ventricles of Wistar Kyoto rats (WKY), spontaneously hypertensive rats (SHR) and stroke-prone SHR (SHRSP) at different ages was determined. The Kd and maximal binding for specific binding of [3H]-2-N(2,6-dimethoxyphenoxyethyl)amino-methyl-1,4-benzodioxane and (-)-[3H]dihydroalprenolol in ventricular homogenates of SHR and SHRSP at prehypertensive ages were similar to those of age-matched WKY. With the development of spontaneous hypertension in SHR and SHRSP, there was a significant decrease in the maximal binding for both ligands without a change in Kd. The decrease in maximal binding in SHR and SHRSP at 10 weeks of age was 29 to 38%, compared with age-matched WKY. There was no difference in ventricular (-)-[3H]quinuclidinyl benzilate binding between WKY and SHRSP. Hofstee analysis of the inhibition of ventricular (-)-[3H]dihydroalprenolol binding by practolol demonstrated a specific 51% decrease in ventricular beta-1 receptor density in 10-week-old SHRSP. In addition, the inotropic response to isoproterenol in isolated papillary muscles from SHRSP was significantly smaller than that in WKY. Thus, it is concluded that during the development of spontaneous hypertension in SHR and SHRSP, there is a specific loss in number of cardiac alpha and beta-1 adrenoceptors with a consequently reduced responsiveness of isolated papillary muscles to isoproterenol in SHRSP. These results are compatible with the reported increase in sympathetic outflow to the cardiovascular system in spontaneous hypertension.

Adrenergic alpha-Antagonists↗
PubMed1983

Regional adaptation of muscarinic receptors and choline uptake in brain following repeated administration of diisopropylfluorophosphate and atropine.

The specific [3H]QNB binding and high-affinity uptake of [14C]choline in 8 brain regions (cerebral cortex, hippocampus, hypothalamus, thalamus, striatum, midbrain, cerebellum and brainstem) after repeated administration of DFP and atropine to guinea-pigs were simultaneously measured. Following repeated DFP administration, AChE was markedly depressed in each brain region. In these animals, there was a significant decrease in specific [3H]QNB binding in the cerebral cortex, hippocampus and striatum, whereas the [3H]QNB binding in the rest of brain regions was unchanged. Scatchard analysis revealed a 36% decrease in the Bmax value for the striatal [3H]QNB binding without a change in the Kd value, suggesting a change in the receptor density. In contrast, repeated atropine administration produced a significant enhancement in the [3H]QNB binding only in the hippocampus and striatum. The Bmax value in the striatum increased by 21% without a change in the Kd value. In addition to the receptor alteration, high affinity uptake of [14C]choline in the hippocampus and striatum was significantly decreased by DFP treatment, while that in the striatum increased by atropine treatment. Thus the present study has demonstrated that a prolonged activation and blockade of central muscarinic receptors resulted in specific adaptation in both the receptor density and ACh availability at the synapses in the cerebral cortex, hippocampus and striatum.

Acetylcholinesterase↗
PubMed1983

Effect of ascorbate on the contractile response induced by DMPP in guinea-pig ileal longitudinal muscle strip.

The study concerned the effect of ascorbate on the contractile response induced by DMPP in the guinea-pig ileal longitudinal muscle. At 0.5-10 mM, sodium ascorbate shifted the dose-response curve for DMPP to the left and enhanced the maximum contraction. On the other hand, in the presence of ascorbate, the high potassium (40 mM)-induced contraction was not altered, and the contraction by acetylcholine and histamine in concentrations higher than 1 microM and 0.3 microM, respectively, was slightly reduced. Thus, ascorbate enhanced the contractile response caused by DMPP which induced acetylcholine release from nerve terminals indirectly by stimulating the ganglia of the Auerbach's plexus elements. This potentiating effect of ascorbate was studied with a dual organ bath which was partitioned into two compartments. When the oral half of the muscle strip was directly stimulated by DMPP applied to the oral compartment, a contraction of the unstimulated anal part was observed. This contraction was blocked by atropine or adenosine applied to the unstimulated part. Tetrodotoxin, applied to the stimulated part, abolished the contraction of the unstimulated part. The contraction of the unstimulated part was enhanced by ascorbate applied to the stimulated part but not to the unstimulated part. These results indicate that the contraction observed in the unstimulated part may have been caused by acetylcholine release from cholinergic nerves as a result of conduction of the oral part excitation by DMPP along cholinergic nerve fibers; ascorbate may have affected the ganglion cells in Auerbach's plexus to potentiate the action of DMPP.

Acetylcholine↗
PubMed1983

Unusual trihydroxylated bile acids in urine of patients with liver cirrhosis.

Urine from 20 male patients with liver cirrhosis was analyzed for bile acid constituents by gas chromatography and gas chromatography-mass spectrometry. Five unusual trihydroxy bile acids were found in the urine: norcholic acid in 18; 3 alpha, 7 beta, 12 alpha-trihydroxy-5 beta-cholanoic acid in 9; hyocholic acid in 11; 1 beta, 3 alpha, 12 alpha-trihydroxy-5 beta-cholanoic acid in 12; and allocholic acid in 13 patients. The presence of unusual trihydroxy bile acids was unrelated to the clinical severity of cirrhosis. Norcholic acid was the major trihydroxy bile acid which was found in the urine.

Adult↗
PubMed1983

Basic aggregation properties of washed rat platelets: correlation between aggregation, phospholipid degradation, malondialdehyde, and thromboxane formation.

The basic characteristics of washed rat platelets in aggregation and biochemical responses to thrombin and collagen were investigated. Maximum aggregation response to thrombin and collagen was observed in the presence of 1-3 mM extracellular CA2+. Breakdown of endogenous phospholipids was followed by HPTLC. Phosphatidylinositol degraded most rapidly and greatly, followed by phosphatidylethanolamine, and phosphatidylcholine. Sphingomyelin did not change on stimulation. Formation of malondialdehyde was closely associated with thrombin- and collagen-induced aggregation within the range of the concentration employed. In addition, it was correlated with TXB2 formation and phosphatidylinositol degradation. These results indicated that, despite known species variation, thrombin-induced aggregation is mediated by TXA2 and malondialdehyde formation reflects both cyclo-oxygenase and thromboxane synthase activities, and phospholipid degradation in rat platelets as well as in human platelets.

Animals↗
PubMed1983

Elevated erythrocyte phosphoribosylpyrophosphate and ATP concentrations in Japanese sumo wrestlers.

1. Japanese sumo wrestlers have a diet rich in energy, which results in marked obesity. Their plasma urate and triglyceride levels were significantly elevated. 2. Erythrocyte phosphoribosylpyrophosphate (PRPP) and ATP concentrations in sumo wrestlers were significantly elevated when compared to the levels in control subjects. 3. There were no significant differences in erythrocyte PRPP synthetase (EC 2.7.6.1), purine nucleoside phosphorylase (EC 2.4.2.1) and hypoxanthine guanine phosphoribosyl transferase (EC 2.4.2.8) activities between sumo wrestlers and control subjects. 4. Erythrocyte adenosine kinase (EC 2.7.1.20), adenosine deaminase (EC 3.5.4.4) and adenine phosphoribosyl transferase (EC 2.4.2.7) activities in sumo wrestlers were significantly elevated. 5. It seems that sumo wrestlers have an increased turnover of adenine nucleotides which may contribute to hyperuricaemia.

Adenine Nucleotides↗
PubMed1983

Effect of shakuyaku-kanzoh-toh, a prescription composed of shakuyaku (Paeoniae Radix) and kanzoh (Glycyrrhizae Radix) on guinea pig ileum.

The actions of shakuyaku-kanzoh-toh (SK), a prescription of the traditional Chinese medicine, on an isolated guinea pig ileum were studied by comparing those of shakuyaku (S) (peony root, Paeoniae Radix) and kanzoh (K) (licorice root, Glycyrrhizae Radix). SK, S and K suppressed the neurogenic contractions of ileum induced by electrical stimulation and ganglionic stimulating agents such as DMPP and nicotine. Although S did not influence acetylcholine (ACh)-induced contraction of ileum, K inhibited ACh-induced contraction to the same extent as the neurogenic contraction. Also SK inhibited ACh-induced contraction but its inhibition was smaller than the inhibition of the neurogenic contraction. SK and K inhibited 40 mM KCl-induced contraction of ileum and the specific binding of 3H-QNB on muscarinic receptors in ileum, but S at 3 X 10(-4) and 10(-3) g/ml, which were enough to suppress the neurogenic contraction of ileum, did not inhibit them. These results suggest that the inhibitory actions of S and K on the neurogenic contraction are due to an inhibition of ACh release from cholinergic nerve and an inhibition of ACh action on ileum smooth muscle, respectively, and that the inhibitory actions of SK are responsible for both inhibitions by S and K. The inhibitions of ACh action by SK and K are presumed to be due to inhibitions of ACh binding on muscarinic receptors and of contractile machinery of smooth muscle.

Acetylcholine↗
PubMed1983

Effect of picrotoxin on adrenal catecholamine secretion.

The effect of picrotoxin (PT) on catecholamine (CA) secretion was investigated in perfused bovine adrenal glands. A low dose of PT (3 microM) enhanced the CA secretion evoked by a 15-min exposure to 1,1-dimethyl-4-phenylpiperazinium (DMPP, a nicotinic agonist; 0.1 mM), but a higher dose (0.3 mM) of PT inhibited the DMPP-evoked CA secretion. The rate of decline of secretory response to the prolonged DMPP stimulation was also accelerated by a higher dose (0.1 mM) of PT. In the dose-response curves for DMPP-evoked CA secretion, the inhibitory action of PT (0.3-1 mM) was more prominent at high doses than at low doses of DMPP. The inhibition pattern was similar to the pattern of a barbiturates blockade. In separate experiments, PT (0.1 mM) augmented calcium (10 mM)- and high potassium (56 mM)-evoked secretory responses. Spontaneous CA secretion was unaffected by PT at the concentrations indicated above. These results indicate that a low dose of PT potentiates, but higher doses inhibit, the adrenal CA secretion by a nicotinic agonist and that the inhibitory effect of PT resembles that of barbiturates.

Adrenal Glands↗
PubMed1983

Cloning of antibiotic-resistance genes in Streptomyces.

Antibiotic-resistance genes were shotgun cloned from antibiotic-producing Streptomyces sp. using pock-forming plasmids (pSF689 and pSF765), as cloning vectors. Streptomyces chartreusis SF1623 and S. lividans 66 were used as host strains. The ribostamycin (RSM) resistance gene was cloned from S. ribosidificus SF733 DNA (on a 2.3 Md PstI fragment) into both S. chartreusis SF1623 and S. lividans 66, using pSF689 as vector. Kanamycin (KM), novobiocin (NB), destomycin (DM) and racemomycin (RM) resistance genes were cloned from S. kanamyceticus M1164, S. spheroides M1469, S. rimofaciens M1470 and S. lavendulae A249 genomic DNA into S. lividans 66, using pSF765 as vector. Furthermore two types of KM resistance determinants derived from S. kanamyceticus M1164 were cloned using S. lividans 66, the pSF689 vector. The RSM resistance gene showed no homology to plasmid pSF733 of S. ribosidificus SF733, but hybridized to PstI or BclI digested total DNA of S. ribosidificus SF733.

Anti-Bacterial Agents↗