Variation in activity of monoamine metabolizing enzymes in rat liver during pregnancy.
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TLDR
It seems possible that the changes in endocrine function which occur during pregnancy are responsible for the observed alterations in enzyme activity.Abstract:
1 Catechol-0-methyltransferase (COMT) and monoamine oxidase (MAO) activities in rat liver were measured during pregnancy, parturition and postpartum Compared with activity in non-pregnant controls, both enzymes showed a significant decrease in activity which was most pronounced at day 18 2 The metabolism of intravenously infused [3H]-adrenaline to [3H]-metanephrine and to [3H]-acidic metabolites was also significantly depressed during pregnancy but had returned to control values by the 21st day 3 The effects of reserpine and/or nialamide on hepatic COMT and MAO were studied in control and 20-day-pregnant rats Their action on COMT activity differed in the two groups MAO was inhibited to a similar extent in these groups whether the drugs were given separately or in combination 4 It seems possible that the changes in endocrine function which occur during pregnancy are responsible for the observed alterations in enzyme activityread more
Citations
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Journal Article
Catechol-O-methyltransferase (COMT): biochemistry, molecular biology, pharmacology, and clinical efficacy of the new selective COMT inhibitors.
Pekka T. Männistö,Seppo Kaakkola +1 more
TL;DR: The enzyme responsible for the O- methylation, catechol- O -methyltransferase (COMT) was partly purified and characterized by the same group as EC, which first described the enzyme-catalyzed O-methylation of catechlamines and other catechols in the late 1950s.
Journal ArticleDOI
Characterization and implications of estrogenic down-regulation of human catechol-O-methyltransferase gene transcription.
TL;DR: These findings provide the first evidence and molecular mechanism for estrogen to inhibit COMT gene transcription, which may shed new insight into the role of estrogen in the pathophysiology of different human disorders.
Journal ArticleDOI
Human liver catechol-O-methyltransferase pharmacogenetics.
TL;DR: Findings indicate that the genetic polymorphism that controls catechol‐O‐methyltransferase activity level and thermal stability in red blood cells also controls those same properties of the enzyme in the human liver.
Journal ArticleDOI
Drug metabolism under pathological and abnormal physiological states in animals and man.
TL;DR: The author recommends the use of female rats in the evaluation of the effects of pathological states on hepatic microsomal drug-metabolizing enzymes, as changes in activity of the hepatic enzymes reflect closely the changes in the rates of drug metabolism in vivo.
Book ChapterDOI
Characteristics of catechol O-methyltransferase (COMT) and properties of selective COMT inhibitors
Pekka T. Männistö,I. Ulmanen,Kenneth Lundstrom,Jyrki Taskinen,Jukka Tenhunen,Carola Tilgmann,Seppo Kaakkola +6 more
TL;DR: The enzyme-catalyzed O-methylation of catecholamines was first described by Axelrod and coworkers in the late 1950’s and was extensively reviewed by Guldberg and Marsden in 1975.
References
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U. S. von Euler,F. Lishajko +1 more
TL;DR: By the addition of small amounts of ethylene diamine (EDA) to the alkali-ascorbic acid mixture used in the trihydroxyindole (THI) method the discoloration of reaction mixture and instability of fluorescence can be prevented, allowing blanks to maintain their fluorescence values for several hours.
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A sensitive and specific assay for the estimation of monoamine oxidase.
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U. S. v. Euler,F. Lishajko +1 more
TL;DR: Nerve granules are more sensitive to temperature than adrenal medullary granules but show higher resistance to freezing and thawing and osmotic changes, and noradrenaline is rapidly released even at low temperature at pH 4 and below, and by detergents.
Journal Article
The physiological disposition of H3-epinephrine and its metabolite metanephrine.
TL;DR: The disappearance of H 3 -epinephrine from plasma after an intravenous injection has two phases: an initial rapid fall, reflecting diffusion into tissues and O-methylation, followed by a slower decline indicating a gradual release from binding sites and concurrent metabolism.
Journal ArticleDOI
Interactions Between Estrogens and Catechol Amines III. Studies on the Methylation of Catechol Estrogens, Catechol Amines and other Catechols by the Catechol-O-Methyltransferase1 of Human Liver
TL;DR: The substrate specificity of the catechol-O-methyltransferase, purified from human liver 380-fold, has been tested with a variety of compounds, and under standard assay conditions, 2-hydroxy-17β-estradiol was the preferred substrate for the enzyme, as compared with epinephrine and other catechols tested.