Studies on Free Amino Acids in Human Brain

Okumura, Nikichi; Otsuki, Saburo; Kameyama, Akira

doi:10.1093/oxfordjournals.jbchem.a127068

Cited by 94 publications

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“…The taurine content of human tissues at various stages of life has rarely been studied [9,10,12], It has been shown that, as in mammals [7,14], the taurine content of most tissues is higher during the fetal and neonatal periods than during adult life [14], and our results concord with this finding. The average taurine concentration which we found in the brain, muscle and liver at var ious gestational stages does not differ from available data [4,7,9,12,14], Changes in taurine content in the brain and the liver of the human fetus were studied during the sec ond semester of gestation [12], and a signifi- Table 4.…”

Section: Discussionsupporting

confidence: 88%

“…It has been shown that taurine levels in frozen autopsy samples do not differ from the values found in immediate biopsy samples [11,12]. Conventional methods were used to deter mine the taurine concentration of the tissues [4,9,10,12,14], Before analysis, 2 g of fragments of brain, liver and muscle were dissected with a scalpel, pulver ized dry at +4 °C then mixed with 2 ml distilled water for 5 min using a Potter type apparatus. The product was then ultrasonicated and centrifuged twice at 6,500 rpm for 15 min.…”

Section: Methodsmentioning

confidence: 99%

“…tal periods [1,3,4,6], By determining the changes in taurine concentration in the main storage organs according to the length of ges tation and after birth, and by taking into account the growth of these organs, we can assess the quantities of taurine that should be supplied during the First months of life. The taurine content of the principal organs during the fetal period and after birth is well known (7,9,10,12], However, these studies do not indicate gestational age and usually only deal with a limited number of subjects. As far as we are aware, only 1 study has ana lyzed the changes in taurine content of the liver and the brain according to fetal devel…”

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confidence: 99%

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Taurine in Developing Brain, Liver and Muscle in Infants

et al. 1989

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In order to evaluate tissue taurine storage during pregnancy, we determined the taurine concentration of a skeletal muscle (abdominal wall), the brain (left parietal lobe), and the liver (right lobe) in 41 children aged 1–10 days, born after 24–41 weeks gestation. Samples were obtained during autopsy. Taurine dosage was carried out by gas chromatography. Muscle and liver taurine concentrations decreased with the duration of gestation. For a given duration of pregnancy, there was no correlation between birth weight and these three tissue concentrations. From these results, we estimate that the fetus accumulates 35–40 μmol/24 h of taurine during the last 3 months of gestation.

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Section: Discussionsupporting

confidence: 88%

Section: Methodsmentioning

confidence: 99%

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Taurine in Developing Brain, Liver and Muscle in Infants

et al. 1989

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“…In human fetuses, during the period of gestation studied, this situation is reversed: the concentration of cystathionine in liver is higher than that in brain for two reasons: (1) the concentration of cystathionine in fetal liver is higher than that in adult liver, and (2) the concentration of cystathionine in fetal brain is lower than that in adult brain. The latter finding in the 24 fetuses that we studied confirms the findings in the 2 fetuses studied by Okumura et al [18]. Our results differ from those of Ryan and Carver [22] who reported concentrations of methionine in human fetal liver (22-24 weeks of gestation) which are far higher than any that we found.…”

Section: Concentrations Of Cystathionine In Tissues and Fluidssupporting

confidence: 68%

“…Little cystathionine is present in liver of mature humans [3,30]. A single report presented fragmentary evidence that the concentration of cystathionine in human fetal brain might be lower than that in brain of mature humans [18]. We have therefore examined the development of the transsulfuration pathway in 58 human fetuses obtained at therapeutic abortion during approximately the 2nd-6th month of gestation and in liver from 5 full term and 3 prematurely born infants.…”

Section: Introductionmentioning

confidence: 99%

Development of Mammalian Sulfur Metabolism: Absence of Cystathionase in Human Fetal Tissues

1972

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ExtractCystathionase activity was absent from human fetal liver and brain as early as 6 weeks of gestation. Hepatic methionine-activating enzyme (26 ± 3 nmoles/mg protein/hr) and hepatic cystathionine synthase (21 ± 4 nmoles/mg protein/hr) were present (cf. 86 ±16 and 98 ± 19 nmoles/mg protein/hr, respectively, in mature human liver). All three activities were absent from the placenta. Human fetal liver contained higher concentrations of cystathionine (14 ± 2 /xmoles/100 g wet weight) than mature human liver (0) and human fetal brain (4.0 ± 0.6 ,umoles/100 g wet weight). Methionineactivating enzyme of human fetal brain, but not liver, showed a tendency to increase with development (coefficient of correlation was 0.62; 0.01 < P < 0.05).35 S-L-methionine injected into the umbilical vein of six human fetuses was incorporated into free methionine in liver and brain, but not into free cyst(e)ine, homocyst(e)ine, taurine or, except for the smallest fetus, cystathionine. 35S-L-cysteine similarly injected was incorporated into free cysteine in liver and brain to a greater extent than in plasma, whereas it was incorporated into cystine in plasma to a greater extent than in either liver or brain. Incorporation of S-L-cysteine incubated with minced liver from four human fetuses showed more active incorporation of methionine (11,836-15,045 dpm/mg protein) than cysteine (7,044-9,856 dpm/mg protein). SpeculationThese studies suggest that cysteine is an essential amino acid in human fetuses and in infants for some time after birth, especially if they were born prematurely. Introductionknown about the early development of these pathways. Although there is considerable information on controlIn normal adult humans, about 90% of ingested meof the metabolism of sulfur-containing amino acids thionine is converted to cyst(e)ine [21], a nonessential and transsulfuration in mature humans, little is amino acid, via the transsulfuration pathway (Fig. 1).

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Vitamin B6 Deficiency and Dependency in Man

Scriver¹

1967

Arch Pediatr Adolesc Med

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Studies on Free Amino Acids in Human Brain

Cited by 94 publications

References 0 publications

Taurine in Developing Brain, Liver and Muscle in Infants

Taurine in Developing Brain, Liver and Muscle in Infants

Development of Mammalian Sulfur Metabolism: Absence of Cystathionase in Human Fetal Tissues

Vitamin B6 Deficiency and Dependency in Man

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