scholarly journals Incorporation of label from d-β-hydroxy-[14C]butyrate and [3-14C]acetoacetate into amino acids in rat brain in vivo

1971 ◽  
Vol 122 (2) ◽  
pp. 135-138 ◽  
Author(s):  
Jill E. Cremer
Keyword(s):  
Amino Acids ◽  
Rat Brain ◽  
Intravenous Injection ◽  
Ketone Bodies ◽  
Specific Radioactivity ◽  
Total Radioactivity ◽  
Soluble Material ◽  
The Brain

The metabolism of ketone bodies by rat brain was studied in vivo. Rats starved for 48h were given either d-β-hydroxy[3-14C]butyrate or [3-14C]acetoacetate by intravenous injection and killed after 3 or 10min. Total radioactivity in the acid-soluble material of the brain and the specific radioactivities of the brain amino acids glutamate, glutamine, aspartate and γ-aminobutyrate were determined. A group of fed animals were also given d-β-hydroxy[3-14C]butyrate. In the brains of all animals 14C was present in the acid-soluble material and the specific radioactivity of glutamate was greater than that of glutamine.

scholarly journals Inhibition of sterol but not fatty acid synthesis by valproate in developing rat brain in vivo

1990 ◽  
Vol 272 (1) ◽  
pp. 251-253 ◽  
Author(s):  
J P Bolaños ◽  
J M Medina ◽  
D H Williamson
Keyword(s):  
Fatty Acid ◽  
Rat Brain ◽  
Fatty Acid Synthesis ◽  
Ketone Bodies ◽  
Acid Synthesis ◽  
Sterol Synthesis ◽  
Weanling Rats ◽  
Developing Rat ◽  
The Brain

The effect of administration of valproate on lipogenesis in the developing rat brain in vivo was studied. Valproate inhibited by 21-38% the rate of 3H2O incorporation into brain sterols, without significantly affecting fatty acid synthesis. Similarly, R-[2-14C]mevalonate incorporation into sterols was inhibited by 33-54%; the low rate of fatty acid synthesis under these conditions was not affected by valproate. Plasma ketone bodies decreased after treatment with valproate. Valproate inhibited (about 50%) both sterol and fatty acid synthesis in livers of weanling rats. It is concluded that valproate can specifically inhibit sterol synthesis in the brain during development, in part at a stage after mevalonate formation, and also by decreased exogenous precursor supply.

scholarly journals The role of leucine in ketogenesis in starved rats

1982 ◽  
Vol 204 (2) ◽  
pp. 399-403 ◽  
Author(s):  
L K Thomas ◽  
M Ittmann ◽  
C Cooper
Keyword(s):  
Intravenous Injection ◽  
Ketone Body ◽  
Ketone Bodies ◽  
Specific Radioactivity ◽  
Body Carbon ◽  
Blood Ketone Bodies

The quantitative significance of the conversion in vivo of L-[U-14C]leucine to ketone bodies was determined in rats starved for 3 or 48 h. In animals starved for 3 h, 4.4% of ketone-body carbon is derived from the metabolism of leucine, and in rats starved for 48 h the corresponding value is 2.3%. This conversion occurs rapidly, and the specific radioactivity of ketone bodies in blood is maximal at 2 min after the intravenous injection of labelled leucine for both periods of starvation. The flux of leucine in the blood is 1.01 and 1.04 mumol/min per 100 g body wt. respectively for animals starved for 3 and 48 h. The specific radioactivity of blood ketone bodies was compared at 2 min after the injection of labelled leucine, lysine and phenylalanine. The specific radioactivity was 4-5 fold higher with leucine than with lysine or phenylalanine.

Movement of [U-14C]glucose Carbon into and Subsequent Release from lipids and High-Molecular-Weight Constituents of Rat Brain, Liver, and Heart In Vivo

1972 ◽  
Vol 50 (1) ◽  
pp. 91-105 ◽  
Author(s):  
R. Vrba ◽  
Anna Winter
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Rat Brain ◽  
High Molecular Weight ◽  
High Speed ◽  
Time Course ◽  
Specific Radioactivity ◽  
Brain Proteins ◽  
Glucose Carbon

After subcutaneous injection of [U-14C]glucose into rats the amount of 14C incorporated in vivo into proteins was always higher than into lipids in brain, liver, and heart. The specific radioactivity of brain proteins was higher than those of liver and heart. Blood-brain comparisons show that protein carbon is derived continuously from glucose in the brain in situ and not as a result of deposition of amino acids or proteins from the circulation. Seventy-two percent of 14C in purified brain protein fractions was found in the amino acids of the hydrolysates of these fractions, mainly in alanine, glutamic, and aspartic acids. Maximum labelling was reached about 4 h after injection of [U-14C]glucose. Elimination of 14C from three classes of brain proteins (high-speed supernatant, particulate deoxycholate extractable, and residual) followed a biphasic time-course. The extent of labelling of, and the rate of elimination of 14C from, the three classes of rat brain proteins were very similar. The fate of 14C in the other investigated tissue fractions of brain, liver, and heart was compared with the fate of 14C in brain proteins.The results lend further support to the previously published suggestion that: (a) brain does not contain appreciable amounts of metabolically inert proteins or of proteins with turnover rates significantly higher than the mean for the bulk of brain proteins; (b) glucose carbon participates at a different rate and to a different extent in the metabolism of high-molecular-weight constituents of brain as compared to liver, heart, and plasma proteins; (c) the continuous conversion of glucose carbon into protein is an important part of the maintenance of the homeostasis of tissue proteins in vivo.

scholarly journals Ketone-body utilization by adult and suckling rat brain in vivo

1971 ◽  
Vol 122 (1) ◽  
pp. 13-18 ◽  
Author(s):  
R. A. Hawkins ◽  
D. H. Williamson ◽  
H. A. Krebs
Keyword(s):  
Rat Brain ◽  
Ketone Body ◽  
Ketone Bodies ◽  
Venous Blood ◽  
Adult Rats ◽  
Suckling Rats ◽  
Arterial Blood ◽  
The Brain ◽  
Body Concentration

1. Ketone-body utilization in fed and starved adult and suckling rats has been investigated by measuring arterio-venous differences across the brain. Venous blood was collected from the confluence of sinuses and arterial blood from the femoral artery in adult rats and by cardiac puncture in suckling rats. 2. During starvation the arterio-venous difference of ketone bodies increased in proportion to their concentrations in the blood and reached a value of 0.16mm at 48h. At a given concentration of the respective ketone bodies the arterio-venous differences of acetoacetate were about twice those of 3-hydroxybutyrate. 3. Fed rats in which the concentrations of ketone bodies were raised by intravenous infusion of sodium acetoacetate had the same arterio-venous differences as starved rats at corresponding ketone-body concentrations. Thus the ability of the rat brain to utilize ketone bodies is independent of the nutritional state. 4. The concentrations of glucose, acetoacetate and 3-hydroxybutyrate were much lower in the brain than in the arterial blood. The measured (blood concentration)/(brain concentration) ratio was 4.4 for glucose, 4.5 for acetoacetate and 8.1 for 3-hydroxybutyrate in 48h-starved rats. 5. The mean arterio-venous difference of glucose across the brain was 0.51mm in fed rats and 0.43mm in 96h-starved rats. 6. Conversion of glucose into lactate rose from negligible values in the fed state to 0.2mm after 48h starvation and decreased to zero after 96h starvation. 7. In 16–22-day-old suckling rats the arterio-venous differences of ketone bodies across the brain were also proportional to the ketone-body concentration, but they were about 3–4 times greater than in adult rats at the same blood ketone-body concentration. 8. Arterio-venous differences of glucose were about the same in adult and suckling rats. 9. The brain of fed suckling rats formed more lactate from glucose than fed adult rats. 10. The results indicate that ketone bodies are major metabolic fuels of the brain of the suckling rat under normal conditions.

scholarly journals Measurement of Cerebral Blood Flow in the Rat with Intravenous Injection of [11C]Butanol by External Coincidence Counting: A Repeatable and Noninvasive Method in the Brain

1984 ◽  
Vol 4 (2) ◽  
pp. 275-283 ◽  
Author(s):  
Shigeharu Takagi ◽  
Kazumasa Ehara ◽  
Peter J. Kenny ◽  
Ronald D. Finn ◽  
Paresh J. Kothari ◽  
...  
Keyword(s):  
Blood Flow ◽  
Rat Brain ◽  
Intravenous Injection ◽  
Regression Line ◽  
Oxygen Extraction Fraction ◽  
Minimum Loss ◽  
Coincidence Counting ◽  
Extraction Fraction ◽  
The Brain ◽  
Large Vessels

No method has been reported for measuring CBF, repeatedly and noninvasively, in the rat brain. A new method is described, which is noninvasive to the brain, skull, or cervical large vessels. Two pairs of coincidence detectors were positioned, one over the rat brain and the other at the loop of a catheter inserted into the femoral artery. The coincidence head curve and arterial curve were recorded after intravenous injection of 1-[11C]butanol in 15 rats. CBF was calculated by one-compartment curve fitting (CBFo) from 1-min data and with the recirculation corrected height/area method from 3-min data (CBFh · 3min) and 5-min data (CBFh · 5min). CBFo agreed well with CBFh · 5min, although a slight overestimation was observed in CBFh · 3min. The normal CBFo in the normocapnic group (n = 6, paco2 36.7 ± 2.3 mm Hg) was 1.76 ± 0.49 ml/g min (mean ± SD). A good correlation was observed between CBFo ( y) and Paco2 ( x), and the regression line was y = 0.0629 x – 0.715 (r = 0.88, p < 0.0001). We concluded that this method gives the stable blood flow values noninvasively and with a minimum loss of blood (<0.28 ml per measurement). Applications of this method include activation studies, studies on the effect of drugs and treatments, and water and oxygen extraction fraction studies using different tracers in the same rat.

scholarly journals Some biochemical effects of triamcinolone acetonide on rat liver and muscle

1970 ◽  
Vol 116 (3) ◽  
pp. 349-355 ◽  
Author(s):  
R. F. Peters ◽  
M. C. Richardson ◽  
Margaret Small ◽  
A. M. White
Keyword(s):  
Amino Acids ◽  
Triamcinolone Acetonide ◽  
Time Course ◽  
Muscle Protein ◽  
Specific Radioactivity ◽  
Synthetic Activity ◽  
Tissue Homogenate ◽  
Glycogen Concentration

1. The powerful anti-inflammatory glucocorticoid triamcinolone acetonide, administered to rats at 20 and 2.5mg/kg, leads to a decrease in the incorporation in vivo of [3H]uridine and [32P]orthophosphate into hind-limb skeletal muscle. 2. At the higher dose, this decrease in the rate of incorporation of precursors into RNA precedes a decrease in the incorporating ability of muscle ribosomes, which commences about 4–5h after drug administration, but is unaccompanied by any changes in the concentration of tissue ATP or free amino acids. 3. The ribosomal dysfunction extends to polyribosomes, which can only be successfully isolated from the muscle of triamcinolone-treated animals after the addition of α-amylase to the tissue homogenate to remove glycogen. 4. The specific radioactivity of muscle protein labelled in vivo with 14C-labelled amino acids does not decrease progressively after triamcinolone administration. After 2h there is an apparent stimulation of incorporation which leads to an overall discrepancy between measurements of protein-synthetic activity made in vivo and in vitro. 5. There is a significant increase in muscle-glycogen concentration between 8 and 12h after the administration of triamcinolone acetonide (20mg/kg), although a significant decrease occurs after 4h. The fall in glycogen concentration may be due to a decrease in the rate of synthesis of protein essential for glucose uptake into the tissues. 6. As judged by (a) incorporation of 14C-labelled amino acids into protein, (b) [3H]uridine and [32P]-orthophosphate incorporation into RNA, (c) the rate of induction of tryptophan pyrrolase and (d) changes in the pool sizes of taurine and tryptophan, the responses in liver followed the same time-course as those in muscle after administration of the drug.

scholarly journals CONCOMITANT SYNTHESIS OF MEMBRANE PROTEIN AND EXPORTABLE PROTEIN OF THE SECRETORY GRANULE IN RAT PAROTID GLAND

1971 ◽  
Vol 50 (1) ◽  
pp. 187-200 ◽  
Author(s):  
Abraham Amsterdam ◽  
Michael Schramm ◽  
Itzhak Ohad ◽  
Yoram Salomon ◽  
Zvi Selinger
Keyword(s):  
Amino Acids ◽  
Secretory Granule ◽  
De Novo ◽  
Secretory Granules ◽  
Specific Radioactivity ◽  
Staining Intensity ◽  
Granule Membrane ◽  
Rat Parotid ◽  
Cell Fractions

After enzyme secretion the membrane of the secretory granule, which had been fused to the cell membrane, was resorbed into the cell. Experiments were therefore carried out to test whether formation of new secretory granules involves reutilization of the resorbed membrane or synthesis of a new membrane, de novo, from amino acids. Incorporation of amino acids-14C into proteins of various cell fractions was measured in vivo, 30, 120, and. 300 min after labeling. At all times the specific radioactivity of the secretory granule membrane was about equal to that of the granule's exportable content. At 120 and 300 min the specific radioactivity of the granule membrane and of the granule content was much higher than that of any other subcellular fraction. It is therefore concluded that the protein of the membrane is synthesized de novo concomitantly with the exportable protein. The proteins of the granule membrane could be distinguished from those of the granule content by gel electrophoresis. All major bands were labeled proportionately to their staining intensity. The amino acid composition of the secretory granule membrane was markedly different from that of the granule's content and also from that of the mitochondrial membrane. The granule membrane showed a high proline content, 30 moles/100 moles amino acids. The analyses show that the radioactivity of the granule membrane is indeed inherent in its proteins and is not due to contamination by other fractions. The possibility is considered that the exportable protein leaves the endoplasmic reticulum already enveloped by the newly synthesized membrane.

scholarly journals Conversion of ethanolamine, monomethylethanolamine and dimethylethanolamine to choline-containing compounds by neurons in culture and by the rat brain

1989 ◽  
Vol 264 (2) ◽  
pp. 555-562 ◽  
Author(s):  
C Andriamampandry ◽  
L Freysz ◽  
J N Kanfer ◽  
H Dreyfus ◽  
R Massarelli
Keyword(s):  
Rat Brain ◽  
Primary Culture ◽  
De Novo ◽  
Water Soluble ◽  
Intraventricular Injection ◽  
Chick Embryos ◽  
Fetal Rat ◽  
Derivatives Of ◽  
The Brain

The incubation of neurons from chick embryos in primary culture with [3H]ethanolamine revealed the conversion of this base into monomethyl, dimethyl and choline derivatives, including the corresponding free bases. Labelling with [methyl-3H]monomethylethanolamine and [methyl-3H]dimethylethanolamine supported the conclusion that in chick neuron cultures, phosphoethanolamine appears to be the preferential substrate for methylation, rather than ethanolamine or phosphatidylethanolamine. The methylation of the latter two compounds, in particular that of phosphatidylethanolamine, was seemingly stopped at the level of their monomethyl derivatives. Fetal rat neurons in primary culture incubated with [3H]ethanolamine showed similar results to those observed with chick neurones. However, phosphoethanolamine and phosphatidylethanolamine and, to a lesser extent, free ethanolamine, appeared to be possible substrates for methylation reactions. The methylation of water-soluble ethanolamine compounds de novo was further confirmed by experiments performed in vivo by intraventricular injection of [3H]ethanolamine. Phosphocholine and the monomethyl and dimethyl derivatives of ethanolamine were detected in the brain 15 min after injection.

Decreased labeling of amino acids by inhibition of the utilization of [3H,14C]glucose via the hexosemonophosphate shunt in rat brain in vivo

1984 ◽  
Vol 9 (3) ◽  
pp. 367-385 ◽  
Author(s):  
M. K. Gaitonde ◽  
Margaret D. James ◽  
Gwyneth M. Evans
Keyword(s):  
Amino Acids ◽  
Rat Brain
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