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Biomedical subjects

C Bovina

Publications and source records attributed to C Bovina.

At least 55 records · Page 3Linked to original sources
PubMed1979

Polyglutamate forms of folate in liver of folic acid-deficient rats.

In view of role played by pteroylpolyglutamates as actual folate coenzymes in single-carbon unit metabolism, the effect of folic acid deficiency on the distribution of these compounds in rat liver has been studied. In deficient rats the liver levels of pteroylpolyglutamates and in particular of those containing a higher number of glutamyl residues are more decreased as compared with monoglutamates. In fact penta- and other higher polyglutamates: mono-, di- and tri-glutamates ratio is lower in deficient rats than that in control rats. The decreased amount of these coenzymic forms observed in this condition may be considered as the consequence of the severe alterations of process which adds glutamate moieties to monoglutamate forms.

Animals↗
PubMed1979

Studies on folate metabolism in folic acid-deficient rats.

The distribution in liver of pteroylpolyglutamates and urinary excretion of folate metabolites was studied in folic acid deficient rats after injection of the vitamin, in order to evaluate the effect of folic acid deficiency on the conversion of the vitamin into actual coenzymic forms. Any significant difference neither in total activity nor in pteroylpolyglutamates of liver does not appear between deficient supplemented and unsupplemented animals. Also the urinary amounts of reduced metabolites in deficient rats do not increase after injection of folic acid. Therefore the inability of deficient rat liver to synthesize polyglutamates may be ascribed to the lower availability of tetrahydrofolates as they are the preferred substrates of pteroylpolyglutamate synthetase.

Animals↗
PubMed1975

Folate metabolism in the rat liver during regeneration after partial hepatectomy.

1. Folate metabolism was studied during the early phases of liver regeneration after partial hepatectomy in rats accustomed to eating during the first 8h of a daily 12h dark period. 2. The content of 5-CH(3)-H(4)folate was drastically decreased during the first hours of regeneration. 3. The total HCO-H(4)folate coenzymes showed a constant decrease during the first 3 days of regeneration, and a continuous interconversion between 5-HCO-H(4)folate and 10-HCO-H(4)folate. 4. 10-HCO-H(4)folate synthetase, serine hydroxymethyl-transferase and 5,10-CH(2)-H(4)folate dehydrogenase activities were relatively low during the first hours after the operation, and increased only several hours later. 5. The increase in enzyme activities showed a stepwise pattern, apparently due to an interaction between the regeneration process and the controlled feeding schedules.

Animals↗
PubMed1972

Effects of testosterone on the metabolism of folate coenzymes in the rat.

1. The effects of castration and testosterone treatment on enzymic activities involved in folate coenzyme metabolism in the liver and in accessory sex organs of male adult rats were studied. 2. In the liver of castrated rats the concentration of 10-formyltetrahydrofolate (10-HCO-H(4)folate) synthetase and tetrahydrofolate (H(4)folate) dehydrogenase were significantly decreased whereas that of 5,10-methylenetetrahydrofolate dehydrogenase increased; the treatment with five doses of testosterone caused a return to normal values of these activities. 3. In the prostate of castrated rats a pronounced decrease in H(4)folate dehydrogenase, serine hydroxymethyltransferase and 10-HCO-H(4)folate synthetase activities was observed. The administration of testosterone restored the enzymic activities to normal values. 4. In the seminal vesicles of castrated rats only 10-HCO-H(4)folate synthetase was markedly depressed; testosterone treatment not only restored activity to normal values but raised it to higher than normal values. The slight changes observed in other enzymic activities also returned to normal values with the hormone treatment. 5. These results are discussed in relation to a possible control mechanism of folate metabolism by testosterone.

Animals↗
PubMed1970

Effects of thyroxine on the synthesis of folate coenzymes in rat liver.

1. The effects of thyroidectomy and of ;acute' and ;chronic' administration of thyroxine on the synthesis of folate coenzymes were studied by determining the liver contents of folate active derivatives and the enzymic activities involved in their biosynthesis. The effect of thyroxine on the same enzymes in vitro was also studied. 2. In thyroidectomized rats the liver contents of folate coenzymes did not change except for a slight decrease in the contents of 5-formyltetrahydrofolate and tetrahydrofolate compared with those in control rats. 3. In the same animals serine hydroxymethyltransferase and formyltetrahydrofolate synthetase activities decreased markedly. 4. The ;chronic' administration of thyroxine to thyroidectomized rats caused more evident variations in the liver contents of folate coenzymes and in particular a decrease in the contents of 5-formyltetrahydrofolate, tetrahydrofolate, 5(or 10)-formyl derivatives of tetrahydropteroylpolyglutamate and of 5(or 10)-formyl derivatives of pteroylpolyglutamate. 5. The enzymic activities did not show significant variations. 6. The ;acute' administration of thyroxine caused changes in the liver contents of some folate derivatives such as 10-formyldihydrofolate, 10-formylfolate, tetrahydrofolate and the 10-formyl derivative of dihydropteroylpolyglutamate. In these animals also the enzymic activities were unchanged. 7. No effect of thyroxine on enzymic activities in vitro was observed.

Animals↗