Uptake of some amino acids by rat brain slices: Effect of various substrates

The uptake of [14C]glycine by slices of mammalian spinal cord

“…The present results show that the mammalian spinal cord possesses the ability to concentrate glycine from an external medium, and also confirm several previous reports that other areas of the brain possess an uptake mechanism for this amino acid (Blasberg & Lajtha, 1965;Smith, 1967;Kandera, Levi & Lajtha, 1968;Barbosa, Joanny & Corriol, 1968).…”

Nonketotic Hyperglycinemia: An in vitro Study of the Glycine-serine Conversion in Liver of Three Patients and the Effect of Dietary Methionine

“…The observation that the response of plasma glycine was only unambiguous 6 days after methionine administration may be related to a restricted permeability of glycine across cell membranes as seen in chick embryo heart [11] and rat brain slices [2].…”

“…They measured the rate of conversion of glycine to serine and carbon dioxide after injecting intravenously glycine labeled with 14 C in the 1 or 2 position. The authors postulated a defect in the oxidation of carbon 1 of glycine to CO 2 and a defect in the conversion of carbon 2 of glycine to carbon 3 of serine. This is consistent with nonfunction of reaction 1 in the following scheme: Further information concerning the enzymic basis of this disease can be obtained by direct measurement of the rates of these reactions in a liver biopsy specimen.…”

Influx of γ‐Aminobutyric Acid and α‐Aminoisobutyric Acid into Mouse Cerebrum Slices Incubated in a Pyruvate Medium with or without Added Glucose or Glucose Analogues Compared with Influx from a Glucose Medium

“…The uptake of amino acids by brain slices is often diminished if glucose is omitted from the incubation medium or is replaced by another energy source (Abadom and Scholefield, 1962a.h; Barbosa et al, 1968;Banay-Schwartz et al, 1974). To test for a specific effect of glucose apart from its role as an energy source, the initial influx of amino acids into mouse cerebrum slices incubated in a pyruvate medium with or without glucose or glucose analogues was measured relative to influx into slices incubated in a similar glucose medium.…”

“…analogue, and by 2-DOG, a glucose analogue that blocks glycolysis ( Table 1). It is difficult to study interactions between amino acid transport and glucose transport in brain slices, because amino acid uptake by this preparation, unlike amino acid uptake by rings of small intestine or kidney cortex slices, etc., is greatly reduced in the absence of glucose or another energy source (Abadom and Scholefield, 1962u,b; Barbosa et al, 1968;Banay-Schwartz et al, 1976;Teller et al, 1977). Analogues such as 2-DOG or 3-0-MeG cannot be considered to be merely nonmetabolizable or partly metabolizable glucose with perhaps somewhat different values for their kinetic pa-rameters.…”