When 1-, 2- and 9-month-old rats adapted to a stock diet were fed a fat-free/high-sucrose diet, the changes in the substrate and effector levels of glycolytic and lipogenic enzymes in liver, and the effects of aging on the changes were investigated. By the sucrose diet feeding, the activities of phosphofructokinase, pyruvate kinase and fructokinase were increased, whereas hexokinase activity was markedly decreased. The fructose 1-phosphate levels were significantly increased in the liver, while conversely, the glucose 6-phosphate and fructose 6-phosphate levels were decreased. As a result of sucrose diet feeding, the changed enzyme activities would appear to be consistent with the metabolic pathway for fructose being predominant over that for glucose. Consequently, the concentrations of acetyl-CoA, citrate and malate were increased and would in turn appear to favour an increase in lipogenesis. The changes in the substrate and effector levels of lipogenic enzymes were reduced with aging, as were those in the enzyme activities. However, the changes in enzyme activities and metabolite levels of glycolysis were not much affected with aging.

Acetyl-CoA Carboxylase↗

PubMed1984

[Quantitative measurement of lung density with X-ray CT and positron CT. (1) Normal subjects].

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Humans↗

PubMed1984

Properties of the depolarization induced by TRH in the isolated frog spinal cord.

We observed the excitatory effects of thyrotropin-releasing hormone (TRH) on isolated, intraarterially perfused spinal cords of frogs. TRH (10(-7)-10(-3) M) produced a transient depolarization and potentiated the spontaneous activities in both the ventral and dorsal roots. The TRH effects were related to both direct and indirect actions, and Na+ deficiency attenuated the direct actions. Serotonin was the only neurotransmitter candidate with which TRH exhibited an interaction. Iproniazid potentiated the TRH effects, in normal Ringer's solution. These results indicate that the TRH depolarization due to direct actions is Na+ dependent, and that indirect actions involve an interaction with a monoaminergic pathway.

Animals↗

PubMed1984

Malignant granular cell tumor of the right sciatic nerve. Report of an autopsy case with electron microscopic, immunohistochemical, and enzyme histochemical studies.

An autopsy case of a malignant granular cell tumor of the right sciatic nerve was reported. The surgically excised malignant granular cell tumor of a 43-year-old women showed a close relationship with the sciatic nerve, and postmortem examination disclosed extensive metastases. Electron microscopic observations of the material obtained at surgery revealed many diagnostic granules containing myelin figures, as well as basement membrane-like structures around some of the tumor cells. Electron microscopic acid phosphatase staining suggested that the granules could be of a lysosomal origin. Immunohistochemical investigation showed the presence of S-100 protein in the tumor cells, a finding which is believed to be specific for the nervous system. And, focally, the cytoplasmic processes accompanied by basement membrane mimicked Schwann cells. This evidence suggested the highly malignant nature of the malignant granular cell tumor of probable Schwann cell origin.

Adult↗

PubMed1984

Comparative study of lipogenic enzymes in several vertebrates.

The liver lipogenic enzymes are compared among rats, chickens, frogs and fish. Although the apparent Km values of glucose-6-phosphate dehydrogenase for glucose-6-phosphate are not much different among all the species, those of malic enzyme for malate are much higher in chickens and fish than in rats and frogs. Glucose-6-phosphate dehydrogenase showed very high activities compared with malic enzyme in fish liver, and malic enzyme showed high activities in chicken liver. Although the apparent Km values of acetyl-CoA carboxylase and fatty acid synthetase for substrates are in the same range among all the animals, the activity of acetyl-CoA carboxylase seems to be extremely low in fish and frog livers, and that of fatty acid synthetase is low in frog livers only. In addition, the apparent Km values of alpha-glycerophosphate acyltransferase of fish liver are very high, and the enzyme activity appears to be extremely low compared to the others. Therefore, the enzymes at the first steps of both fatty acid and glycerolipid syntheses of poikilothermos animals appear to be very low. On the other hand, the Ouchterlony double-diffusion patterns showed that the lipogenic enzymes of chickens, frogs and fish are immunologically different from those of rats, with the exception of acetyl-CoA carboxylase in chickens. Therefore, it is suggested that the fatty acid and glycerolipid forming systems of poikilothermos animals are quite different from those of homoiothermos and the lipogenesis is very low in poikilothermos.

Acetates↗

PubMed1984

Effect of methamphetamine on rat spinal cord. Dopamine receptor-mediated depression of monosynaptic reflex.

The experiments were performed on spinal rats transected at Cl. Intravenous administration of methamphetamine-HCl (MA-HCl, 2 mg/kg) and apomorphine-HCl (5 mg/kg) reduced the amplitude of the monosynaptic reflex (MSR), while the polysynaptic reflex was increased by methamphetamine. Depression of the monosynaptic reflex by both drugs was antagonized by haloperidol, but not by phentolamine. Depression of the monosynaptic reflex by methamphetamine was not antagonized by pretreatment with reserpine; however, the result was explained by the assumption that methamphetamine releases newly-synthesized dopamine or that methamphetamine may act directly on dopamine receptors. Depression of the monosynaptic reflex induced by methamphetamine was independent of peripheral changes in blood pressure. Oxygen tension in the spinal cord was slightly reduced by methamphetamine in rats treated with phentolamine and a change of pO2 in the spinal cord was ruled out as a possible mechanism of action. These results suggest that dopaminergic neurons in the spinal cord of the rat depress the transmission of monosynaptic spinal reflexes.

Animals↗

PubMed1984

Brain cyclic nucleotides and the development of convulsion, with reference to the anticonvulsant activity of diazepam.

Dibutyryl cyclic GMP (DbcGMP) or dibutyryl cyclic AMP (DbcAMP) given to mice intracerebroventricularly in a dose of 200 or 400 nmol/head produced electroencephalographic and electromyographic changes corresponding to twitches, and clonic and tonic convulsions. Lower doses of DbcGMP or DbcAMP facilitated the pentylenetetrazol-induced clonic and tonic convulsions. Diazepam given intraperitoneally in a dose of 0.5 mg/kg suppressed clonic and tonic convulsions induced by DbcGMP and DbcAMP, but the twitches were not suppressed. These results suggest that these nucleotides lower the threshold for electrical discharges related to convulsion and facilitate the propagation of convulsion. Diazepam suppresses this facilitation.

Animals↗

PubMed1984

LSD but not methysergide reduces the inhibitory effect of the medullary raphe stimulation on the spinal reflex in rats.

Conditioning stimulation of the nucleus raphe in the rat medulla enhanced the monosynaptic reflex (MSR) and depressed the polysynaptic reflex (PSR) in separate time courses. The PSR decreasing effect was reduced in preparations pretreated with reserpine, PCPA, or 5,6-DHT. The MSR increasing effect was not altered by these three pretreatments. Intravenously administered LSD but not methysergide reduced the PSR decreasing effect with no influence on the MSR increasing effect. These two drugs had similar effects on the unconditioned responses; the MSR was decreased and the PSR was increased. Thus, the PSR decreasing effect seems to be mediated via a serotonergic pathway probably descending from the nucleus raphe.

Animals↗