scholarly journals Lipid synthesis in vivo by tissues of the maternal and foetal guinea pig

1976 ◽  
Vol 154 (1) ◽  
pp. 159-161 ◽  
Author(s):  
C T Jones ◽  
W Firmin
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Guinea Pig ◽  
Lipid Synthesis ◽  
Short Chain Fatty Acids ◽  
Adipose Tissues ◽  
Pig Liver ◽  
Foetal Liver ◽  
Guinea Pig Liver

The rate of lipid biosynthesis in vivo was determined in pregnant guinea pigs after maternal and foetal injections of 3H2O. Synthesis in the maternal tissues was low and in the foetal liver and adipose tissues relatively high. In the foetal liver it reached a peak at about two-thirds of gestation, whereas that in the foetal adipose tissue occurred later. These results were used to support the view that lipid synthesis in the foetal guinea-pig liver at two-thirds of gestation is largely from short-chain fatty acids, whereas in foetal adipose tissue glucose is probably the major substrate.

Convenient biosynthetic preparation of isomeric spin-labelled radioactive phosphatidic acids

1982 ◽  
Vol 60 (11) ◽  
pp. 1014-1017 ◽  
Author(s):  
L. Stuhne-Sekalec ◽  
N. Z. Stanacev
Keyword(s):  
Fatty Acids ◽  
Guinea Pig ◽  
Stearic Acid ◽  
Liver Microsomes ◽  
Enzymatic Preparation ◽  
Pig Liver ◽  
Secondary Hydroxyl ◽  
Phosphatidic Acids ◽  
Guinea Pig Liver Microsomes ◽  
Guinea Pig Liver

A convenient method for the enzymatic preparation of sn-3-[2-3H]phosphatidic acids carrying also 5-, 12-, or 16-nitroxide stearic acids, from sn-3-[2-3H]glycerophosphate and isolated guinea pig liver microsomes, is described in detail. The procedure allows a simultaneous preparation of three spin-labelled sn-3-[2-3H] phosphatidic acids of yields 3–3.5 μmol of each compound which is > 99% pure in respect to the radioactivity and which contains 25 mol% of spin-labelled fatty acids. These phosphatidic acids were approximately equally distributed between the primary and the secondary hydroxyl when 12- or 16-nitroxide stearic acids were used or predominantly (75%) associated with the secondary hydroxyl of sn-3-[2-3H]phosphatidic acid when 5-nitroxide stearic acid was present in the incubation mixture.

scholarly journals Development of fatty acid oxidation in neonatal guinea-pig liver

1982 ◽  
Vol 208 (3) ◽  
pp. 723-730 ◽  
Author(s):  
D A Shipp ◽  
M Parameswaran ◽  
I J Arinze
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Guinea Pig ◽  
Ketone Bodies ◽  
Liver Mitochondria ◽  
Fatty Acyl ◽  
Acid Oxidation ◽  
Beta Oxidation ◽  
Pig Liver ◽  
Guinea Pig Liver

The capacity of foetal and neonatal liver to oxidize short-, medium- and long-chain fatty acids was studied in the guinea pig. Liver mitochondria from foetal and newborn animals were unable to synthesize ketone bodies from octanoate, but octanoylcarnitine and palmitoylcarnitine were readily ketogenic. The ketogenic capacity at 24 h after birth was as high as in adult animals. Hepatocytes isolated from term animals were unable to oxidize fatty acids, but at 6 h after birth production of 14CO2, acid-soluble products and acetoacetate from 1-14C-labelled fatty acids was 40-50% of the rates at 24 h. At 12 h of age these rates had already reached the 24 h values and did not change during suckling in the first week of life. The activities of hepatic fatty acyl-CoA synthetases, which were minimal in the foetus or at term, increased to maximal values in 12-24 h. The data show that the capacity for beta-oxidation and ketogenesis develops maximally in this species during the first 6-12 h after birth, and appears to be partly dependent on the development of fatty acid-activating enzyme.

scholarly journals The osmotic stability of lysosomes from adult and foetal guinea-pig liver tissue

1969 ◽  
Vol 111 (4) ◽  
pp. 503-507 ◽  
Author(s):  
Julienne M. Turnbull ◽  
M. W. Neil
Keyword(s):  
Guinea Pig ◽  
Liver Tissue ◽  
Marker Enzyme ◽  
Pig Liver ◽  
Nitrophenyl Phosphate ◽  
Osmotic Stability ◽  
Activity Measurements ◽  
Foetal Liver ◽  
Instability Characteristic ◽  
Guinea Pig Liver

1. Lysosome-rich fractions were obtained from foetal liver tissues as early as 35 days uterine age. Foetal lysosomes showed the same ‘structure-linked latency’ and acid hydrolytic potentiality characteristic of their adult counterparts. 2. The osmotic stability of lysosome-rich fraction from foetal guinea-pig liver tissue was greater than that of the corresponding adult lysosome fractions, p-nitrophenyl-phosphatase being used as marker enzyme. 3. The observation was confirmed by using β-glycerophosphatase and phenolphthalein β-glucuronidase as alternative marker enzymes. p-Nitrophenyl phosphate and β-glycerophosphate appear to act as substrates for the same enzyme. 4. By using p-nitrophenylphosphatase activity measurements it was shown that the osmotic stability of foetal lysosomal fractions decreased with increasing foetal age, but at no time achieved the degree of osmotic instability characteristic of adult lysosomal fractions. 5. The correlation of these findings with the intracellular environment of lysosomes is discussed.

scholarly journals Durable Normal Erythropoiesis in Organotypic Cultures of Guinea Pig Foetal Liver

Blood ◽  
1969 ◽  
Vol 34 (4) ◽  
pp. 472-476 ◽  
Author(s):  
GERMANO SALVATORELLI ◽  
ANNA MARIA GULINATI ◽  
PAOLO DEL GRANDE
Keyword(s):  
Stem Cells ◽  
Guinea Pig ◽  
Normal Serum ◽  
Organotypic Cultures ◽  
Pig Liver ◽  
Foetal Liver ◽  
Undifferentiated Cells ◽  
Guinea Pig Liver ◽  
Pig Serum ◽  
Stimulation Of

Abstract It is demonstrated that anemic guinea pig serum maintains erythropoiesis in organotypic cultures of fetal guinea pig liver for at least 14 days. The action of the anemic serum seems be due to the stimulation of the differentiation of stem-cells into erythroblasts. If fetal guinea pig liver is cultured on normal serum the cytodifferentiation stops during the first days of culture whereas the maturation of normoblasts can continue for a few days. The number of stem-cells diminishes considerably and after 4 days they all disappear. On the contrary in culture on anemic serum, their number is unaltered even after two weeks in culture and this seems to indicate that the anemic serum displays a favorable action in the maintenance of the pool of undifferentiated cells in the explants.

scholarly journals Regulation of gluconeogenesis and lipogenesis. The regulation of mitochondrial pyruvate metabolism in guinea-pig liver synthesizing precursors for gluconeogenesis

1969 ◽  
Vol 112 (4) ◽  
pp. 435-447 ◽  
Author(s):  
Ethel W. Somberg ◽  
Myron A. Mehlman
Keyword(s):  
Fatty Acids ◽  
Guinea Pig ◽  
Organic Acids ◽  
Pyruvate Carboxylase ◽  
Liver Mitochondria ◽  
Carbon Chain ◽  
Carbon Chain Length ◽  
Metabolite Formation ◽  
Pig Liver ◽  
Guinea Pig Liver

1. The carboxylation of pyruvate to oxaloacetate by pyruvate carboxylase in guinea-pig liver mitochondria was determined by measuring the amount of 14C from H14CO3− fixed into organic acids in the presence of pyruvate, ATP, Mg2+ and Pi. The main products of pyruvate carboxylation were malate, fumarate and citrate. Pyruvate utilization, metabolite formation and incorporation of 14C from H14CO3− into these metabolites in the presence and the absence of ATP were examined. The synthesis of phosphoenolpyruvate from pyruvate and bicarbonate is minimal during continued oxidation of pyruvate. Larger amounts of phosphoenolpyruvate are formed from α-oxoglutarate than from pyruvate. Addition of glutamate, α-oxoglutarate or fumarate did not appreciably increase formation of phosphoenolpyruvate when pyruvate was used as substrate. With α-oxoglutarate as substrate addition of fumarate resulted in increased formation of phosphoenolpyruvate, whereas addition of succinate inhibited phosphoenolpyruvate formation. In the presence of added oxaloacetate guinea-pig liver mitochondria synthesized phosphoenolpyruvate in amount sufficiently high to play an appreciable role in gluconeogenesis. 2. Addition of fatty acids of increasing carbon chain length caused a strong inhibition of pyruvate oxidation and phosphoenolpyruvate formation, and greatly promoted carbon dioxide fixation and malate, citrate and acetoacetate accumulation. The incorporation of 14C from H14CO3−, [1−14C]pyruvate and [2−14C]pyruvate into organic acids formed was examined. 3. It is concluded that guinea-pig liver pyruvate carboxylase contributes significantly to gluconeogenesis and that fatty acids and metabolites play an important role in its regulation.

scholarly journals The availability of carnitine acetyltransferase in mitochondria from guinea-pig liver and other tissues

1968 ◽  
Vol 110 (4) ◽  
pp. 739-746 ◽  
Author(s):  
P. J. Barker ◽  
N. J. Fincham ◽  
D C Hardwick
Keyword(s):  
Guinea Pig ◽  
Glutamate Dehydrogenase ◽  
Freeze Drying ◽  
Enzymic Activity ◽  
Carnitine Acetyltransferase ◽  
Cell Cytoplasm ◽  
Pig Liver ◽  
Triton X ◽  
Guinea Pig Liver

The carnitine acetyltransferase and glutamate dehydrogenase activities of guinea-pig liver and other tissues were estimated. Both enzymes are wholly mitochondrial, and can only be fully observed after disruption of the mitochondrion. Triton X-100 (0·1%) or freeze-drying revealed more activity than other methods tried. In mitochondria prepared and suspended in 0·25m-sucrose and in cell cytoplasm only small fractions of the total enzymic activity could be observed in guinea-pig liver: on average 7·5% of carnitine acetyltransferase and 5·5% of glutamate dehydrogenase. It is concluded that, in liver or mammary gland of goat, guinea pig or rat, little or no carnitine acetyltransferase is available in vivo to acetyl-CoA outside the mitochondrion.

scholarly journals Effect of physiological reducing compounds on the inactivation of tyrosine aminotransferase from guinea-pig liver*

1982 ◽  
Vol 205 (2) ◽  
pp. 265-269 ◽  
Author(s):  
D Di Cola ◽  
G Federici
Keyword(s):  
Guinea Pig ◽  
Reduced Glutathione ◽  
Tyrosine Aminotransferase ◽  
Enzyme Inactivation ◽  
Inactivation Rate ◽  
Physiological Concentration ◽  
Pig Liver ◽  
Microsomal Membranes ◽  
Guinea Pig Liver

1. Tyrosine aminotransferase from guinea-pig liver is inactivated at neutral pH by a factor localized in the microsomal fraction. The inactivation, independent of exogenous L-cysteine, is rapidly reversed by addition of dithiothreitol. 2. The effects of physiological reducing agents on the enzyme inactivation were investigated. L-Cysteine and L-cysteamine enhance the inactivation rate of the enzyme in the presence of microsomal membranes, and also they are able to bring about the loss in enzyme activity independently of microsomal action. Reduced glutathione, at physiological concentration, and NADPH decrease the inactivation rate. Other physiological reducing compounds, as well as oxidized glutathione and NADP+, are without effect. 3. Neither reduced glutathione nor NADPH, unlike dithiothreitol and mercaptoethanol, is able to restore the activity of partially inactivated tyrosine aminotransferase. 4. It is proposed that the intracellular concentration of reduced glutathione might modulate the rate of inactivation of the enzyme in vivo.

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