Changes in ornithine transcarbamylase activity and protein level during perinatal period in rat liver. Effects of actinomycin D

Belbekouche, M; Gautier, C.; Vaillant, R.

doi:10.1016/0006-291x(85)91960-6

Cited by 4 publications

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“…This enzyme activity was found in the liver and placenta of wild-type mice from the 16th day of gestational age and both activities were significantly related. This progressive increase with gestational age has been previously described by others (Belbekouche et al, 1985;Miller and Chu, 1970) for fetal rat liver. Three lines of evidence pointed out the similarity of OTC obtained from placenta and liver: (i) a similar K , value for Orn and CP in both tissues; (ii) a very low placental activity in S p P h mice; and (iii) a similar pH dependence of the enzyme from the liver and placenta.…”

Section: Discussionsupporting

confidence: 80%

Prenatal diagnosis of ornithine transcarbamylase deficiency: Results in SPF^ASH mice

1993

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Ornithine transcarbamylase (OTC) deficiency is a human X-chromosome-linked disease (McKusick 31125). The presence of OTC activity in the human placenta encouraged us to examine the possible diagnosis of the disease in an animal model (Spfash mice) by enzymatic assay on placental samples. A significant positive correlation (p < 0.02) was found between placental and hepatic activities; the pH dependence of OTC was similar in the placenta and liver when compared within normal or homozygous mutant mice. The apparent Km (ornithine) and Km (carbamoylphosphate) values of the enzyme did not show any significant differences when compared in both placentae and livers of normal fetuses. The use of OTC assay in the placenta for prenatal diagnosis of OTC deficiency in mouse fetuses obtained by the crossbreeding of Spfash/+ with +/Y has shown that our method has good diagnostic value. We made the diagnosis of OTC deficiency in male fetuses with a sensitivity and a specificity of 1.0. The + gene from the father in Spfash/+ animals is preferentially inactivated in extraembryonic tissues, explaining why very low placental OTC activity was observed in 12 of the 18 female fetuses studied. Because these 12 females have variable OTC activity in their livers, it is not possible to appreciate the true residual activity in their livers by measuring this activity in the placenta.

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Section: Discussionsupporting

confidence: 80%

Prenatal diagnosis of ornithine transcarbamylase deficiency: Results in SPF^ASH mice

1993

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Regulation of argininosuccinate synthetase level by corticosteroid and pancreatic hormones during perinatal period

et al. 1995

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The urea cycle takes place in the hepatocyte of ureothelic animals. The conversion of ammonia into urea involves five reactions. The first 2 take place in the matrix of the mitochondria, the last 2 occur in the cytosol. Argininosuccinate synthetase (AS) is the third reaction of the urea cycle. It catalyses the condensation of citrulline and aspartate into argininosuccinate. We have previously reported that rat AS activity was present in the cytosol and the outer membrane of the mitochondria. We have shown that, at the activity level, the colocation of AS was changing during fetal and neonatal development and was under the control of corticosteroid and pancreatic hormones. However, an unresolved issue was whether both AS had the same specific activity and that their location was changing during ontogenesis or that the specific activities of mitochondrial and cytosolic enzymes were different and/or modified during this period. In the present report, we compared the compartmentalization of AS activity and protein level in the fetus, the new-born and the adult rat and the role of corticosteroid and pancreatic hormones. Specific activities of both AS remained unchanged during ontogenesis. Glucocorticoids induced an increase in mitochondrial AS while glucagon appeared to induce a concomitant decrease in the level of mitochondrial AS and an increase in cytosolic AS.

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Demonstration of argininosuccinate synthetase activity associated with mitochondrial membrane: Characterization and hormonal regulation

et al. 1994

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Argininosuccinate synthetase (AS) is the third enzyme in ureogenesis, it catalyses the reaction of condensation of citrulline and aspartate into argininosuccinate. In the present report, we described the first characterization of AS within the outer membrane of rat liver mitochondria. Mitochondria-associated AS displayed the same kinetic characteristics as the cytoplasmic enzyme, but was found to be thermostable while cytoplasmic AS was not. The evolution of the co-location of AS was analyzed during ontogenesis. Total AS activity increased throughout rat fetal development. Simultaneously, the subcellular distribution of the enzyme has changed. AS activity was mainly mitochondrial in fetal and new-born liver liver and cytoplasmic in adult rat liver. The variation in subcellular distribution of AS may be due to the dramatic changes in hormonal levels that occur during this period. The role of corticosteroid and pancreatic hormones was studied. During fetal period, corticosteroid hormones induced an increase in mitochondria-associated AS activity. This was prevented by insulin. Glucagon did not modify total AS activity but reduced mitochondrial AS activity, meanwhile, a comparable increase in cytoplasmic AS activity was observed. One may hypothesize that glucagon may participate in the transfer of mitochondrial enzyme into the cytosol.

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Changes in ornithine transcarbamylase activity and protein level during perinatal period in rat liver. Effects of actinomycin D

Cited by 4 publications

References 19 publications

Prenatal diagnosis of ornithine transcarbamylase deficiency: Results in SPF^ASH mice

Prenatal diagnosis of ornithine transcarbamylase deficiency: Results in SPF^ASH mice

Regulation of argininosuccinate synthetase level by corticosteroid and pancreatic hormones during perinatal period

Demonstration of argininosuccinate synthetase activity associated with mitochondrial membrane: Characterization and hormonal regulation

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Changes in ornithine transcarbamylase activity and protein level during perinatal period in rat liver. Effects of actinomycin D

Cited by 4 publications

References 19 publications

Prenatal diagnosis of ornithine transcarbamylase deficiency: Results in SPFASH mice

Prenatal diagnosis of ornithine transcarbamylase deficiency: Results in SPFASH mice

Regulation of argininosuccinate synthetase level by corticosteroid and pancreatic hormones during perinatal period

Demonstration of argininosuccinate synthetase activity associated with mitochondrial membrane: Characterization and hormonal regulation

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Prenatal diagnosis of ornithine transcarbamylase deficiency: Results in SPF^ASH mice

Prenatal diagnosis of ornithine transcarbamylase deficiency: Results in SPF^ASH mice