Showing papers on "Catechol-O-methyl transferase published in 1980"

Monoamine oxidase and catechol-O-methyltransferase activities in cultured fibroblasts and blood cells from children with autism and the Gilles de la Tourette syndrome

Abstract: Monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT) activities were measured in cells from children with autism (n = 5) and the Gilles de la Tourette syndrome (n = 5). Monoamine oxidase activities in cultured skin fibroblasts (type A) and platelets (type B) from the same individual were not correlated. COMT activities in fibroblasts and red blood cells showed a negative but not significant correlation (r = -0.42). Fibroblast MAO and COMT activities from patients were similar to values from controls matched for age, race, and sex. Increasing clinical severity of illness in both disorders, however, correlated significantly with higher fibroblast MAE activity. Cultured fibroblasts provide a means of measuring enzyme activities independently of the individual's current physiological and psychological state.

Catechol-O-methyltransferase and catecholamines in anxiety and relaxation

Abstract: Levels of anxiety, plasma epinephrine and norepinephrine, and red blood cell (RBC) catechol-O-methyltransferase (COMT) activity were measured before and after 4 weeks of relaxation training in a group of 15 drug-free, anxious subjects and at a similar interval in a group of 15 drug-free, healthy controls. The index group showed significant decreases in levels of anxiety and plasma epinephrine and norepinephrine after treatment. No changes were observed in the control values. RBC COMT did not show any significant differences in activity between the index and control groups and between the pre- and posttreatment values. Similarly, COMT activity levels failed to correlate with levels of anxiety and catecholamines before or after treatment. These findings indicate that anxiety is unlikely to have an effect on RBC COMT activity, whereas it has a direct effect on plasma catecholamines.

Developmental patterns of catechol-O-methyltransferase in genetically different rat strains: enzymatic and immunochemical studies.

Abstract: Catechol-O-methyltransferase (COMT) activity in the liver and kidneys of adult Fischer-344 (F-344) rats is only half of that in the same organs of Wistar-Furth (W-F) rats. The trait of low COMT activity in these animals is inherited in an autosomal recessive fashion. A comprehensive study of patterns of change in COMT activity during growth and development was performed to determine whether "temporal gene" effects might play a role in the inherited differences in enzyme activity present in adult animals. The COMT activity expressed per mg protein in liver and kidneys of newborn F-344 rats is only 50-60% of that in the same organs of W-F animals. The liver and the kidneys of newborn rats of both strains have COMT activity an order of magnitude higher than those in brain, heart, or blood. In addition, in both strains there are much larger increases in liver and kidney COMT activities during growth and development (5-10 fold) than in blood, brain, or heart (one- to twofold). Immunotitration with antibodies against rat COMT demonstrates that differences in immunoreactive COMT parallel differences in COMT activity, both between strains and within strains during growth and development. However, when the temporal patterns of change in enzyme activities in the liver and the kidneys of the two strains of rat are compared at multiple times during growth and development, no differences in the patterns are present. These results make it unlikely that temporal gene effects can explain the inherited differences in COMT activity in liver and kidneys of F-344 and W-F rats.

Anti-catechol-O-methyltransferase: demonstration of specificity and immunological cross-reactivity with the enzyme from rat liver, kidney, brain, and choroid plexuses.

Abstract: An antiserum to rat liver catechol-O-methyltransferase (COMT) was utilized in the immunological characterization of COMT from rat kidney, brain, and choroid plexuses, in addition to rat liver. The presence of anti-COMT activity was confirmed by the direct inhibition of the activity of the enzyme from rat liver by small quantities of the antiserum and by the inhibition of the activity of the enzyme from rat brain. The specificity of the antiserum was demonstrated both by immunoelectrophoresis of rat liver COMT, and by a partial purification of rat liver COMT in which changes in COMT specific activity were correlated with the appearance of a precipitin line in double-immunodiffusion experiments. The antigenic similarity of the enzyme derived from rat liver, kidney, brain, and choroid plexuses was demonstrated by the formation of a precipitin line of identity when preparations from these four tissues were diffused against the antiserum.

Influence of Hypo- and Hyperthyroidism on Noradrenaline Metabolism in Brown Adipose Tissue of the Developing Rat

Abstract: We studied the noradrenaline content, and monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT) activities in brown adipose tissue (BAT) of normal, hypothyroid, and hyperthyroid developing rat. In the newborn, thyroid hormones are necessary for the increase in noradrenaline content which occurs between 0 and 5 days. Hypothyroidism increases both MAO and COMT activities. Hyperthyroidism decreases MAO activity but not noradrenaline content or COMT activity. In the full-term fetus, hypothyroidism decreases noradrenaline content as in the newborn, and also decreases MAO and COMT activities. It is suggested that thyroid hormones could modulate BAT nonshivering thermogenesis by regulating the level of noradrenaline, the direct mediator of heat production.

Hydroxyindole-O-methyltransferase (HIOMT), catechol-O-methyltransferase (COMT) and histamine-N-methyl-transferase (HNMT) in the pineal gland of the vizcacha

Abstract: The activities of three methylating enzymes HIOMT, COMT, and HNMT were determined in pineal glands from 2 groups of adult vizcachas of both sexes, one (I) maintained under permanent lighting (15 days) and the other (II) kept in darkness. The control determinations (III) were carried out in pineal glands from animals hunted and killed during the night.

Methyl conjugation in uraemia: catechol‐O‐methyltransferase.

Abstract: 1 Erythrocyte (RBC) catechol-9-methyltransferase (COMT) activity is significantly higher in erythrocytes from uraemic patients on maintenance haemodialysis, 18.7 +/- 1.4 units/ml RBC (mean +/- s.e. mean, n = 22) than in the blood of randomly selected subjects, 12.0 +/- 0.2 units/ml (mean +/- s.e. mean, n = 557, P < 0.001). 2 Uraemic plasma contains larger quantities of endogenous methyl acceptors than does normal plasma, and it reversibly inhibits RBC lysate COMT activity to a greater degree than does normal plasma. 3 There are large individual variations in the degree of inhibition of RBC COMT activity plasma from patients with renal failure. Inhibition varied from 10-43% when 40 microliters plasma from each of 19 randomly selected uraemic patients was tested, and there as a direct correlation between the inhibition of COMT by plasma from an individual uraemic patient and its content of endogenous methyl acceptors (r = 0.64, n = 19, P < 0.01). 4 Kinetic studies with pooled uraemic plasma demonstrate that inhibition of COMT by uraemic plasma is uncompetitive with respect to both the catechol substrate and the methyl donor for the reaction, S-adenosyl-L-methionine. 5 Plasma from uraemic patients does not inhibit partially purified rat liver COMT, an observation which suggests that the inhibition is not due to a direct effect on COMT but requires the presence of other constituents of the RBC lysate, perhaps other methyltransferase enzymes.