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Biomedical subjects

K Fujimori

Publications and source records attributed to K Fujimori.

At least 217 records · Page 12Linked to original sources
PubMed1986

Inhibition of canine spermatogonial mitosis with follicle regulatory protein.

Evidence was found that the Graafian follicle produces and secretes a hormone-like protein, referred to as follicle regulatory protein (FRP), which affects the responsivity of other follicles to gonadotropin stimulation. Since a similar material was identified in homogenates of bull testes, we evaluated the effects of FRP on the histology of seminiferous epithelium by its systemic injection into normal dogs. Mongrel dogs were injected IM with 5 mg of FRP for 17 consecutive days. The seminiferous epithelium was evaluated by light microscopy and divided into eight stages according to Foote. The relative frequency of stage 4 was significantly less in the FRP-treated than in the control group, but that of stage 7 was significantly greater in the FRP-treated group. The ratios of type B/type A spermatogonia for control and FRP-treated groups for stages 6-8 were 1.5, 5.8, 2.4, and 1.6, 4.3, 1.6, respectively. The tubular diameters of stages 6 and 7 were significantly different between the two groups. The numbers of tubules containing spermatogonial divisions were significantly decreased at stages 2 + 3 and stages 6 + 7 in the FRP-treated group. A clear decrease in the number of tubule profiles with spermatogonial divisions was present at stages 6 and 7 in the FRP-treated testis. Taken together, these findings suggest that FRP inhibits spermatogonial transformation of type A into type B.

Animals↗
PubMed1985

Comparison of sulfide oxygenation mechanism for liver microsomal FAD-containing monooxygenase with that for cytochrome P-450.

Mechanistic mode for the oxygenation of sulfides with the pig liver microsomal FAD-containing monooxygenase(EC 1.14.13.8) has been conveniently distinguished from that with the phenobarbital induced liver microsomal cytochrome P-450 by analyzing products of the oxygenation of phenacyl phenyl sulfide. Upon oxygenation of phenacyl phenyl sulfide, the FAD-containing monooxygenase gave solely phenacyl phenyl sulfoxide in contrast to the cytochrome P-450 promoted oxygenation which is known to give substantial amounts of C-S bond fission products. The observation suggests that the oxygenation of sulfide with FAD-containing monooxygenase involves the nucleophilic attack of the divalent sulfur on the reactive oxygen atom involved at the enzyme active site, namely electrophilic oxygenation of sulfide, though the oxygenation with the cytochrome P-450 is initiated by a single electron transfer from the sulfide to the enzyme active species.

Acetophenones↗
PubMed1985

The basal ganglia in chlordecone-induced neurotoxicity in the mouse.

This overview summarizes the available data concerning the neurotoxic effects of chlordecone on the basal ganglia in mice. Included are the effects of chlordecone on motor coordination, levels of biogenic amines, uptake of catecholamines and GABA, release of 3H-dopamine from striatal slices, newly synthesized dopamine, levels of dopamine metabolites in striatum, total and protein-bound Ca++ in discrete areas of brain, and distribution of chlordecone in discrete areas of brain. These data suggest that the basal ganglia may be the brain site at which chlordecone acts to produce its neurotoxic effects.

Animals↗
PubMed1984

Comparison of hepatic drug-metabolizing enzymes induced by 3-methylcholanthrene and phenobarbital between pre- and postnatal rats.

Effects of 3-methylcholanthrene (3MC) and phenobarbital (PB) on the hepatic drug-metabolizing enzyme system in fetal liver of rats were investigated. Intraperitoneal administration of 3MC (25 mg/kg, 72 and 48 hr before death) to pregnant rats significantly increased hexobarbital (HB) and aminopyrine (AM)-metabolizing activities in fetuses on the 21st day of gestation to 148.0 and 150.6% of control fetuses, respectively. In contrast, HB and AM-metabolizing activities in 4-day-old neonates and mothers were decreased by administration of 3MC on the 21st day of gestation. Benzo[a]pyrene (BP)-metabolizing activity, NADPH-cytochrome c reductase activity, and cytochrome P-450 content in 3MC-treated fetuses were significantly increased to 2143.6, 137.6, and 323.8% of the control, respectively. Following 3MC administration, the maximum absorption of the cytochrome P-450-CO difference spectra in liver microsomes of fetuses was observed at 449-450 nm. The induction profile following 3MC administration in the fetal livers was different from that in the neonatal and the maternal livers. On the other hand, intraperitoneal administration of PB (60 mg/kg, 72, 48, and 24 hr before death) significantly increased HB, AM, and BP-metabolizing activities in fetal livers to 263.7, 231.0, and 151.2% of the respective controls. The profile induced by PB in the fetal livers was similar to that in maternal livers. These results suggest that HB and AM-metabolizing enzymes in fetal livers treated with 3MC or PB possess the capacity to be induced, and the responsiveness of the drug-metabolizing enzyme system to 3MC during the prenatal stage may differ from the postnatal stage.

Aminopyrine↗
PubMed1984

Stimulation of the release of lysosomal and nonlysosomal granular enzymes from macrophages treated with monensin.

Mouse peritoneal macrophages that had been treated with a monovalent carboxylic ionophore, monensin, selectively secreted lysosomal and nonlysosomal granular enzymes into the medium. When macrophages were incubated with 1 to 10 microM monensin, the release of beta-glucuronidase, beta-hexosaminidase and beta-galactosidase was stimulated time and does dependently. Neither the beta-glucosidase nor acid phosphatase, enzymes bound to the lysosomal membranes, however, were released by monensin. Neutral alpha-glucosidase, shown recently to be localized in nonlysosomal granules of macrophages (15), was released by monensin at concentrations lower than those required for lysosomal enzyme release. Increased release of lysosomal enzymes also took place in a manner similar to that seen with monensin-treated macrophages after treatment of macrophages with weak bases, chloroquine and ammonium chloride. Neutral alpha-glucosidase, however, was not released when chloroquine was present in concentrations that stimulated the release of lysosomal enzymes. The UDP-galactosyltransferase activity of the Golgi apparatus in the macrophages markedly decreased after treatment with low concentration of monensin.

Acid Phosphatase↗
PubMed1983

The heterogeneity of arylhydrocarbon hydroxylase in fetal liver microsomes of rats.

The characteristic of arylhydrocarbon hydroxylase system in fetal liver microsomes of rat was investigated. NADH-synergistic effect on NADPH-dependent arylhydrocarbon hydroxylase was observed in fetal liver microsomes of rat but not in maternal liver microsomes. NADH-synergistic effect decreased in parallel with the decrease of the ratio of cytochrome b5/cytochrome P-450 in liver microsomes. The cytochrome P-450 in arylhydrocarbon hydroxylase system in fetal liver microsomes of rat seemed to be different from that in offspring liver microsomes in respect of its dependency on cytochrome b5 system for its maximum activity.

4-Chloromercuribenzenesulfonate↗
PubMed1983

Simultaneous determination of aminopyrine hydroxylation and aminopyrine N-demethylation in liver microsomes by high-performance liquid chromatography.

Aminopyrine and its metabolites, including 3-hydroxymethyl-2-methyl-4-dimethylamino-1-phenyl-3-pyrazoline-5-one which is a hydroxylated metabolite of aminopyrine, were separated on a reversed-phase (C8) Radial-Pak column using a mobile phase of methanol-triethylamine-water (30:1:69) adjusted to pH 5.40 with acetic acid. Detection of the peak was performed by an ultraviolet detector at 254 nm. By the rapid and simple method, aminopyrine hydroxylation as well as aminopyrine N-demethylation in liver microsomes can be examined simultaneously.

Aminopyrine↗
PubMed1983

Cytotoxic effects of methylnitrosourea on developing brain.

The effect of methylnitrosourea (MNU) on cerebellar and cerebral DNA, RNA, protein, lysosomal enzymes (acid DNase, RNase, phosphatase, and beta-glucuronidase), and 2',3'-cyclic nucleotide 3'-phosphohydrolase (2',3'-CNPase) activities was studied in rats from birth through 12 days of age. Subcutaneous injection of MNU in a dose of 0.625 mmol/kg caused a suppression of increase in weights and content of DNA, RNA, and protein of cerebellum, but no changes in those of the cerebrum or in body weight. Ratios of protein and RNA to DNA were substantially elevated by MNU in the cerebellum but not in the cerebrum. Acid DNase and acid RNase activities of MNU-treated rats were significantly elevated beyond the increase of these activities in controls in the cerebellum, but no change in these activities by MNU was observed in the cerebrum. A slight elevation in acid phosphatase activity was observed in the cerebellum but not in the cerebrum after MNU pretreatment. Beta-glucuronidase and 2',3'-CNPase activities were not changed in the cerebellum or in the cerebrum. These results suggest that in the developing brain, especially in the cerebellum at the mitotic stage, MNU caused cell damage and inhibited cell mitosis.

Acid Phosphatase↗