Zur bestimmung der α-ketosäuren in körperflüssigkeiten und geweben

Gründig, E

doi:10.1016/0009-8981(61)90059-6

“…This may also be relevant under physiological conditions because it was shown that the plasma concentration of a-ketoglutarate in man is in the range of 10 to 30 Fmol. L - (18)(19)(20). This concentration may even be higher in portal venous blood because a-ketoglutarate is released from the intestine as a by-product of glutamine breakdown (21).…”

Section: Discussionmentioning

confidence: 95%

“…Also these dicarboxylates are found in human blood and HEPATOCYTEHETEROGENEITYINTRANSPORT 253 plasma at concentrations of 3 to 50 Fmol. L-' (18,19,22). It is likely that delivery of these dicarboxylates by way of the bloodstream may also serve as a carbon source for glutamine synthesis (23).…”

Section: Discussionmentioning

confidence: 99%

Functional hepatocyte heterogeneity in glutamate, aspartate and α-ketoglutarate uptake: A histoautoradiographical study

Stoll

¹

,

McNelly

²

,

Buscher

³

et al. 1991

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[3H]glutamate, [3H]alpha-ketoglutarate or [3H]aspartate was injected in physiological concentrations into antegrade (from portal to hepatic vein) or retrograde (from hepatic to portal vein) perfused rat liver, and the tissue distribution of radioactivity was studied by histoautoradiography. Independent of the direction of perfusion, radioactivity was accumulated in a small perivenous liver parenchymal cell population, which surrounded the terminal hepatic venules as a layer of about two to five cells thick. In contrast, accumulation of radioactivity in periportal hepatocytes was low and sometimes not detectable. This distribution pattern roughly resembled that described for the immunohistochemical distribution of glutamine synthetase in liver. The present histoautoradiographic findings demonstrate a predominant uptake of vascular glutamate, aspartate and ketoglutarate into a small perivenous cell population. They confirm previous label incorporation studies in the metabolically intact liver, demonstrating an almost exclusive uptake of vascular glutamate and alpha-ketoglutarate into perivenous glutamine synthetase containing hepatocytes. In addition, evidence is presented suggesting that perivenous uptake of alpha-ketoglutarate may be one determinant for hepatic glutamine synthesis, at least under the experimental conditions used here.

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“…2, 1991 HEPATOCYTEHETEROGENEITYINTRANSPORT 253 plasma at concentrations of 3 to 50 Fmol. L-' (18,19,22). It is likely that delivery of these dicarboxylates by way of the bloodstream may also serve as a carbon source for glutamine synthesis (23).…”

Section: Discussionmentioning

confidence: 99%

Functional hepatocyte heterogeneity in glutamate, aspartate and α-ketoglutarate uptake: A histoautoradiographical study

Stoll¹

1991

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[3H]glutamate, [3H]alpha-ketoglutarate or [3H]aspartate was injected in physiological concentrations into antegrade (from portal to hepatic vein) or retrograde (from hepatic to portal vein) perfused rat liver, and the tissue distribution of radioactivity was studied by histoautoradiography. Independent of the direction of perfusion, radioactivity was accumulated in a small perivenous liver parenchymal cell population, which surrounded the terminal hepatic venules as a layer of about two to five cells thick. In contrast, accumulation of radioactivity in periportal hepatocytes was low and sometimes not detectable. This distribution pattern roughly resembled that described for the immunohistochemical distribution of glutamine synthetase in liver. The present histoautoradiographic findings demonstrate a predominant uptake of vascular glutamate, aspartate and ketoglutarate into a small perivenous cell population. They confirm previous label incorporation studies in the metabolically intact liver, demonstrating an almost exclusive uptake of vascular glutamate and alpha-ketoglutarate into perivenous glutamine synthetase containing hepatocytes. In addition, evidence is presented suggesting that perivenous uptake of alpha-ketoglutarate may be one determinant for hepatic glutamine synthesis, at least under the experimental conditions used here.

show abstract