Pyruvate carboxylase activity and hypoglycaemia in the neonatal guinea pig

1981 ◽  
Vol 9 (5) ◽  
pp. 399-400 ◽  
Author(s):  
TIMOTHY P. ROLPH ◽  
COLIN T. JONES
1975 ◽  
Vol 146 (2) ◽  
pp. 329-332 ◽  
Author(s):  
D E Saggerson ◽  
C J Evans

1. Measurements are presented of the activity and intracellular distribution of phosphoenolypruvate carboxykinase, pyruvate carboxylase and NADP-malate dehydrogenase in rat, guinea-pig and rabbit liver and kidney cortex, together with previously obtained measurements of these enzymes in adipose tissue. 2. In all three tissues pyruvate carboxylase activity was greatest in the rat and lowest in the rabbit. 3. Guinea pig and rabbit were very similar to each other with respect to the extramitochondrial-mitochondrial distribution of phosphoenolpyruvate carboxykinase in all three tissues. 4. NADP-malate dehydrogenase was present in all three tissues in the rat, present in kidney cortex and adipose tissue in the guinea pig and absent from all tissues examines in the rabbit.


1974 ◽  
Vol 142 (3) ◽  
pp. 477-482 ◽  
Author(s):  
E. David Saggerson

1. Fat-cells isolated from rabbit perirenal adipose tissue were incubated with the following U-14C-labelled substrates: 5mm-glucose (+insulin), 5mm-pyruvate, 5mm-lactate, 5mm-glucose+5mm-acetate (+insulin), and the relative rates of incorporation of these substrates into glyceride fatty acids determined. In general total rates of fatty acid synthesis were similar whatever substrate was supplied to the cells. 2. Rabbit fat-cells incorporated [U-14C]acetate into fatty acids and CO2 as well in the absence of glucose as in the presence of this substrate. 3. The disposition of the utilization of glucose-derived carbon through various metabolic pathways was determined. 4. Extramitochondrial and mitochondrial activities were determined for 11 enzymes. The cells contained a very low activity of pyruvate carboxylase, undetectable NADP–malate dehydrogenase activity and a high mitochondrial phosphoenolpyruvate carboxylase activity. 5. Various rabbit fat-cell metabolic parameters based on the measurement of14C incorporation and enzyme activity were compared with the same parameters previously measured in rat and guinea-pig fat-cells. In general guinea pig occupied a position between rat and rabbit with respect to these parameters. 6. The profiles of substrate incorporation into fatty acids and of relative enzyme activities in rabbit fat-cells indicated that the operation of a ‘citrate-cleavage’ pathway may not be obligatory for the supply of lipogenic acetyl units.


PEDIATRICS ◽  
1972 ◽  
Vol 50 (5) ◽  
pp. 702-711
Author(s):  
Michèle G. Brunette ◽  
Edgard Delvin ◽  
Bernard Hazel ◽  
Charles R. Scriver

The cause of severe intermittent lactic acidosis was investigated in a female infant with profound psychomotor retardation. Hypoglycemia, hyperpyruvic acidemia, and hyperalaninemia were identified in the newborn period. A triad of lactate, pyruvate, and alanine accumulation persisted throughout infancy, and ACTH, anorexia, and high carbohydrate feeding further provoked their accumulation. Careful dietary control or thiamine-HCl supplementation (5 to 20 mg/day) ameliorated the metabolic abnormality. Pyruvate dehydrogenase activity (which is thiamine-dependent) was normal in leukocytes and cultured skin fibroblasts. Hepatic pyruvate carboxylase activity (which is biotin-dependent) was found to comprise more than one component. There was a partial deficiency of total hepatic pyruvate carboxylase activity in the patient. The loss of activity was confined to the low-Km component of the enzyme which serves pvruvate metabolism in the physiological range. A defect in glucogenesis causing hypoglycemia, pyruvate accumulation with lactic acidosis, and aberrant amino acid metabolism can be attributed to the abnormality of pyruvate carboxylase. The response to thiamine in our patients may reflect activation of a normal "shunt" mechanism for pyruvate disposal via pyruvate dehydrogenase.


2009 ◽  
Vol 57 (3) ◽  
pp. 321-333 ◽  
Author(s):  
H. Moussa ◽  
S. EL-Gamal

Treatment with CdCl 2 (0, 100, 400 and 1000 μM) resulted in the inhibition of root dry biomass and root elongation and to increased Cd accumulation in the roots. These treatments also decreased the relative water content, chlorophyll content, 14 CO fixation, phosphoenol pyruvate carboxylase and ribulose-1,5-bisphosphate carboxylase activity and abscisic acid (ABA) content, while increasing the malondialdehyde, hydrogen peroxide and free proline contents and causing changes in the chloroplast and root ultrastructure. Pretreatment of seeds with SA (500 μM) for 20 h resulted in the amelioration of these effects.


1984 ◽  
Vol 16 (2) ◽  
pp. 262-262 ◽  
Author(s):  
U. J. Dijkstra ◽  
J. M. F. Trijbels ◽  
W. Ruitenbeek ◽  
J. A. J. M. Bakkeren ◽  
A. J. M. Janssen ◽  
...  

2005 ◽  
Vol 51 (8) ◽  
pp. 1462-1471 ◽  
Author(s):  
Laurent Knafo ◽  
Philippe Chessex ◽  
Thérèse Rouleau ◽  
Jean-Claude Lavoie

Abstract Background: Parenteral multivitamin preparation (MVP) induces fatty liver in neonatal guinea pig pups; this is prevented by photoprotection. Photo-excited riboflavin present in MVP generates H2O2 and molecules with masses of 136 and 208. We hypothesized that H2O2 initiates the peroxidation of ascorbic acid (AA), producing biologically active byproducts affecting hepatic lipid metabolism. Methods: Mass spectrometry (MS) documented the participation of H2O2 and photo-excited riboflavin (Ribo) in the formation of AA byproducts. Sixteen 3-day-old guinea pig pups received an intravenous solution (50 g/L dextrose + 4.5 g/L NaCl + 1 kIU/L heparin) at 240 mL · kg−1 · day−1, enriched with control or test mixtures, for 4 days. The control mixture was photo-protected AA + Ribo (without byproducts or H2O2), and the test mixture was AA + Ribo treated to generate AA byproducts without H2O2. Hepatic acetyl-CoA carboxylase (ACC) activity was determined after 4 days. Fourth-day urine samples were analyzed by MS. Data were treated by ANOVA (α = 0.05). Results: H2O2 did not influence the classic degradation of AA, as the generation of 2,3-diketogulonic acid was not affected. In contrast, the formation of molecules with masses of 136 and 208 was H2O2 and time dependent. ACC activity was higher (P <0.01) in animals receiving high concentration of these molecules; its hepatic activation correlated (P <0.01) with the urinary concentration of molecule-208. Conclusions: H2O2 at concentrations found in the clinical setting of total parenteral nutrition induce the transformation of dehydroascorbic acid into compounds that have the potential to affect lipid metabolism. These molecules have peroxide and aldehyde functions.


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