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Biomedical subjects

K Oguri

Publications and source records attributed to K Oguri.

At least 127 records · Page 7Linked to original sources
PubMed1985

Highly sulfated proteochondroitin sulfates synthesized in vitro by rat glomeruli.

A previous report from this laboratory (Kobayashi, S., Oguri, K., Kobayashi, K. and Okayama, M. (1983) J. Biol. Chem. 258, 12051-12057) indicated that isolated rat glomeruli synthesized three species of sulfated glycoconjugates in vitro, namely, sulfated glycoproteins, proteoheparan sulfates and proteochondroitin sulfates. In the present study, the proteochondroitin sulfates, which showed the greatest incorporation of [35S]sulfate among the three sulfated glycoconjugates, were isolated and characterized. Radiolabeled tissue proteochondroitin sulfates were clearly separated on Sepharose CL-6B into three components with partition coefficients (Kd) of 0.16, 0.22 and 0.58, and medium proteochondroitin sulfates were separated into two components with Kd values of 0.33 and 0.62. When the chondroitin sulfate chains released by alkaline borohydride treatment were analyzed by digestion with chondroitinase AC-II, chondroitinase ABC, chondro-6-sulfatase and chondro-4-sulfatase, the results showed that all the samples contained glucuronosyl-N-acetylgalactosamine (chondroitinase AC-II-susceptible sequences, 72-86%) and iduronosyl-N-acetylgalactosamine (chondroitinase ABC-susceptible sequences, 14-28%), containing 4-sulfated N-acetylgalactosamine (50-70%) and 4,6-disulfated N-acetylgalactosamine (30-50%). On two-dimensional electrophoresis on cellulose acetate, all samples gave a single spot which closely coincided with chondroitin sulfate E of squid cartilage in electrophoretic mobility. These results indicated that the chains were highly sulfated chondroitin sulfates containing glucuronic acid and iduronic acid residues.

Animals↗
PubMed1984

Potentiation of physical dependence by conjugation at the 6-position of nalorphine.

The experiments concerned the effects of glucuronate or sulfate conjugation at the 6-position of nalorphine on the analgesic and antagonistic activities and also on the development of tolerance and physical dependence. Nalorphine-3-and 6-sulfate ester were synthesized for the first time. The analgesic effect of nalorphine-6-sulfate and -glucuronide was higher than that of nalorphine when assessed in the acetic acid writhing test. However, these 6-conjugates exhibited less potent agonistic activity in the test with guinea-pig ileum muscle strip and revealed no analgesic effect in the tail pinch test. The antagonistic activity of these 6-conjugates to morphine analgesia was lower on their s.c. injection, but higher on i.c.v. injection than that of nalorphine. The development of tolerance to the analgesia caused by nalorphine was not affected by the 6-modifications. Frequent withdrawal signs were seen in mice treated chronically with anlorphine-6-conjugates by challenging with naloxone while mice treated with nalorphine showed no such signs. This potent enhancing effect of 6-conjugation on the development of physical dependence was suggested to be also the case with morphine. These changes of potency due to conjugation were interpreted as due to the altered interaction with multiple opioid receptors.

Analgesics↗
PubMed1984

Studies on N-demethylation of methamphetamine by liver microsomes of guinea-pigs and rats: the role of flavin-containing mono-oxygenase and cytochrome P-450 systems.

Relative participation of flavin-containing mono-oxygenase and cytochrome P-450 systems in N-hydroxylation of and formaldehyde release from methamphetamine were studied in vitro using liver microsomes of guinea-pigs and rats. In guinea pigs, only methimazole, an inhibitor of flavin-containing mono-oxygenase, significantly suppressed the above reactions. Formaldehyde release from methamphetamine was significantly inhibited not only by methimazole but also by inhibitors of the cytochrome P-450 system in liver microsomes from rats, but not guinea-pigs. Pretreatment of guinea-pigs with phenobarbital and 3-methylcholanthrene did not enhance the metabolism of methamphetamine. Pretreatment of rats with phenobarbital but not 3-methylcholanthrene increased slightly the N-demethylation of methamphetamine by liver microsomes. The results indicate that a marked species difference exists in the enzymes concerned with N-demethylation of methamphetamine. N-Oxidation predominates in guinea-pigs, whereas in rats, N-oxidation and C-oxidation of the methyl group participate equally as the initial reaction of the N-demethylation pathway.

Animals↗
PubMed1983

Isolation and characterization of proteoheparan sulfate synthesized in vitro by rat glomeruli.

Glomeruli isolated from rat kidney were incubated with [14C]glucosamine and [35S]sulfate. Linear incorporation of [14C]glucosamine into total glycosaminoglycans was observed during incubation up to 24 h. More than 95% of the 35S-labeled sulfated glycoconjugates were extracted from the tissue with 4 M guanidine HCl, 50 mM sodium acetate, pH 6.0, and 0.5% Triton X-100, and separated clearly on DEAE-Sephacel into three major fractions, i.e. sulfated glycoprotein (11% of the total radioactivity), proteoheparan sulfate (33%), and proteochondroitin sulfate (38%) fractions. The molecular weight of the 35S-labeled proteoheparan sulfate thus isolated was estimated to be about 185,000, whereas that released into the medium was estimated to be about 87,000. When the 35S-labeled heparan sulfate isolated on Sephadex G-75 after mild alkaline borohydride treatment was digested with a combination of heparitinase and heparinase, approximately 70% of the radioactivity was converted to 2-acetamido-2-deoxy-4-O-(alpha-D-gluco-4-enepyranosyluronic acid)-6-O-sulfo-D- glucose.

Animals↗
PubMed1983

The properties of UDP-glucuronyltransferase for cannabinoids in rat liver microsomes.

The glucuronidation of delta 9-tetrahydrocannabinol (delta 9-THC), cannabidiol (CBD) and cannabinol (CBN) in rat liver microsomes was studied. The enzyme activities for the cannabinoids were 26.3 (delta 9-THC), 52.9 (CBD) and 104.8 (CBN) pmol/min/mg protein. The apparent Km values of UDP-glucuronyltransferase for the cannabinoids were 0.29 (delta 9-THC), 0.18 (CBD) and 2.78 (CBN) mM, while Vmax were 40.3 (delta 9-THC), 104.9 (CBD) and 593.3 (CBN) pmol/min/mg protein. Following treatment of rats with 3-methylcholanthrene, the enzyme activities for delta 9-THC, CBD and CBN were increased 132, 43 and 1198%, respectively, whereas the corresponding increases in microsomes from phenobarbital-treated rats were 127, 13 and 97%, respectively. The cannabinoid glucuronidation was activated 2 to 3 folds by the addition of UDP-N-acetylglucosamine, but not activated by the addition of Triton X-100 in vitro. The properties of cannabinoid UDP-glucuronyltransferase were discussed from the above results.

Animals↗
PubMed1983

Increased synthesis of hyaluronic acid by mouse mammary carcinoma cell variants with high metastatic potential.

Variant subpopulations of FM3A mouse mammary carcinoma cells that have increased lung-colonizing potential were obtained previously by sequentially harvesting pulmonary metastases, culturing their cells in vitro, and reestablishing the metastases in vivo. In the present study, glycosaminoglycan production by the parental and variant cells was studied after metabolic labeling of cultures by [14C]glucosamine for 24 hr. Analysis of the products indicated that the rate of incorporation of the labeled precursor into hyaluronic acid in the high-metastatic variant cells was 27 to 54 times the rate in the low-metastatic variant cells and that the increase in hyaluronic acid synthesis was not associated with an increase in the rate of synthesis of other glycosaminoglycans. Both the cell layers and media of high-metastatic variants contained a much higher proportion of radioactivity in hyaluronic acid than did the corresponding fractions of low-metastatic cell lines. The results provide a basis for further investigation of the potential role of hyaluronic acid in control of the behavior of epithelial tumor cells during metastasis.

Animals↗
PubMed1982

Isolation and partial characterization of sulfated glycoproteins synthesized by corneal epithelium.

The corneal epithelia isolated from 19-day-old chick embryos were incubated with [35S]sulfate and [3H]glucosamine. More than 95% of the isotope-labeled sulfated glycoconjugates were extracted with 4 M guanidine/HCl, 50 mM sodium acetate, pH 6.0, and 0.5% Triton X-100 and separated on DEAE-Sepharose CL-6B into two major fractions, i.e. sulfated glycoprotein and sulfated proteoglycan fractions. Mild alkali treatment of the sulfated proteoglycan fraction and characterization of the sulfated glycosaminoglycans enabled the identification of heparan sulfate ([35S], 81%; [3H], 91%) and chondroitin sulfate ([35S], 19%; [3H], 9%). Fractionation of the sulfated glycoprotein fraction on Sepharose CL-6B resulted in the separation of four sulfated glycoproteins with apparent molecular weights of 70,000, 130,000, 280,000, and over 2,000,000. The products of alkaline borohydride treatment of the sulfated glycoproteins separated into three fractions on Sephadex G-75, two fractions contained sulfated oligosaccharides, and the third one contained inorganic sulfate and N-acetyl-galactosaminitol. Incorporation of [35S]sulfate into higher molecular weight fraction of the two fractions was selectively inhibited by tunicamycin, whereas that incorporated into the smaller molecular weight fraction was not inhibited by the drug and, rather, was activated. These results suggest that the former contains N-glycosidically linked sulfated glycopeptides, and the latter is derived from O-glycosidically linked sulfated oligosaccharide side chains.

Animals↗
PubMed1982

A novel metabolite of oxycodone in the urine of rabbits.

In addition to six metabolites of oxycodone which were reported previously, 7 beta-hydroxy-6 beta-oxycodol was further isolated as one of the major metabolites in rabbits. The structure of this novel metabolite was characterized by mass and nuclear magnetic resonance spectra. Such a metabolite possessing vicinal hydroxyl groups in aliphatic ring is very new in the metabolism of narcotic analgesics.

Animals↗
PubMed1982

Determination of oxycodone metabolites in urines and feces of several mammalian species.

Determination of oxycodone metabolites excreted in urines and feces of several mammalian species was studied by use of the tritium labeled compound. It was found that the radioactivity was excreted more in the urines than in the feces in rabbits, guinea pigs and mice, but not in rats, who eliminated it equally into the urines and feces. Most of the radioactivity was excreted in 48 h after the administration. Seven metabolites, oxymorphone, 6 alpha-oxycodol, 6 beta-oxycodol, 7 beta-hydroxy-6 beta-oxycodol, noroxycodone, oxycodone N-oxide, and 6 alpha-oxycodol, N-oxide, as well as well as unchanged oxycodone, were found to be excreted into urines of rabbits in both free and conjugated forms except two N-oxides, which were found only in the free form. It was discussed that analgesic effect of oxycodone would mainly be attributable to the oxycodone itself, but not to the metabolites.

Animals↗
PubMed1981

In vitro and in vivo interactions of delta 8-tetra-hydrocannabinol and its metabolites with hepatic microsomal drug metabolizing enzyme systems of mice.

Interactions of delta 8-tetrahydrocannabinol (delta 8-THC) and its metabolites, 11-hydroxy-delta 8-THC, 11-oxo-delta 8-THC and delta 8-THC-11-oic acid, with hepatic microsomal drug metabolizing enzyme were studied in vitro and in vivo using mice. All the cannabinoids used were shown to produce a type I spectral change of cytochrome P-450 in hepatic microsomes. THe apparent binding affinities (Ks) for delta 8-THC, 11-hydroxy-delta 8-THC, 11-oxo-delta 8-THC and delta 8-THC-11-oic acid were 5.2, 169.6, 33.2 and 148.8 microM, respectively. delta 8-THC, 11-oxo-delta 8-THC and delta 8-THC-11-oic acid (100 microM) caused a significant stimulation of NADPH oxidation in vitro with microsomes. In addition, delta 8-THC (20, 40 and 80 microM) markedly inhibited p-nitroanisole O-demethylase and aniline hydroxylase in microsomes. 11-Hydroxy-delta 8-THC and 11-oxo-delta 8-THC also showed the inhibitory effect, but to lesser extents. Furthermore, single pretreatments with delta 8-THC and 11-oxo-delta 8-THC (30 mg/kg, i.v.) significantly decreased activities of p-nitroanisole O-demethylase and aniline hydroxylase in hepatic microsomes, accompanying a decrease of cytochrome P-450 content in case of delta 8-THC. On the other hand, all these pretreatments except for that with delta 8-THC-11-oic acid showed a stimulatory effect on p-nitrophenol glucuronidation with hepatic microsomes, in contrast to an inhibitory effect in vitro.

Aniline Hydroxylase↗
PubMed1980

UDP-glucuronyltransferase activities of rabbit liver microsomes for cannabinoids.

UDP-glucuronyltransferase activities for delta 8-tetrahydrocannabinol, 11-hydroxy-delta 8-tetrahydrocannabinol, cannabidiol and cannabinol were examined using liver microsomes of rabbits. The activities for cannabidiol and cannabinol were 2.5 and 19 times higher, respectively, than those for delta 8-tetrahydrocannabinol and 11-hydroxy-delta 8-tetrahydrocannabinol. Thus, the present study supports the view that glucuronide formation plays an important role in the metabolism of cannabinol, but does only a minor role in that of delta 8-tetrahydrocannabinol and 11-hydroxy-delta 8-tetrahydrocannabinol.

Animals↗
PubMed1980

Identification and determination of 11-oxo-delta8-tetrahydrocannabinol as an intermediate metabolite of delta8-tetrahydrocannabinol in the mouse brain and liver.

11-Oxo-delta 8-tetrahydrocannabinol (11-oxo-delta THC) was found in the mouse brain and liver extracts as a new in vivo metabolite of delta8-THC. The metabolite was detected by thin-layer chromatography using two aldehyde reagents together with a phenol reagent and identified as a heptafluorobutyrate by ECD-gas chromatography. This identification was further supported by gas chromatography-mass spectrometry. Content of the metabolite in the mouse liver was 0.09 or 0.19 microgram/g at 15 min after the i.v. injection of delta8-THC or 11-hydroxy-delta8-THC (11-OH-delta8-THC) at a dose of 10 mg/kg. On the contrary, 11-oxo-delta 8-THC was not precisely quantified (less than 0.01 microgram/g) in the brain after injection of delta 8-THC, although its content after the injection of 11-OH-delta 8 THC was 0.03 microgram/g.

Animals↗