Dopamine β-Hydroxylase in Rat Serum and Lymph: Changes with Age and Effect of Cold Exposure

Behrens, Willy A.; Depocas, Florent

doi:10.1139/y75-150

Cited by 9 publications

(4 citation statements)

References 10 publications

(11 reference statements)

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“…As already found by others, there is a slight decrease of TH activity in the aging brain (Algen et al, 1977;London et al, 1985). Although DBH activities also decrease with age (Behrens and Delpocas, 1975), the most striking effect is the important decrease of AADC activity. Thus, from birth to old age, the evolution of AADC activities is biphasic: an increase from birth to adulthood (Brus, 1975), then a decrease with aging.…”

Section: Discussionsupporting

confidence: 64%

Effects of Aging on p‐ and m‐Octopamine, Catecholamines, and Their Metabolizing Enzymes in the Rat

David

Coulon

Cavoy

et al. 1989

Journal of Neurochemistry

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Functions of octopamine in the mammalian brain are still not well known. An important aspect of this problem is the relationship between octopamines and catecholamines. Previous data have shown that their respective ontogenic evolutions are not parallel. Do the changes in brain related to aging also differentially affect these two groups of molecules? In order to check this point, the brain levels of p- and m-octopamine, p-tyramine, noradrenaline, and dopamine, as well as the activities of metabolizing enzymes, were determined in young adult and aging rats (20-26 months). Unlike catecholamines, there is a drastic decrease of p-octopamine after 20 months of age in the hypothalamus and telencephalon. p-Tyramine levels are also lowered. This change appears to be due to a decrease of the aromatic L-amino acid decarboxylase activity. These data, as those of ontogenic studies, confirm that p-octopamine and catecholamine metabolisms may have some independent steps and, moreover, that p-octopamine may have a role in the normal activity of the brain.

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Section: Discussionsupporting

confidence: 64%

Effects of Aging on p‐ and m‐Octopamine, Catecholamines, and Their Metabolizing Enzymes in the Rat

David

Coulon

Cavoy

et al. 1989

Journal of Neurochemistry

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“…Separation of the IBAT into right and left pads and removal of muscle, adhering white fat, and some connective tissuc was done in a cold room (5°C) with the tissue on a petri dish in contact with crushed ice. The blotted and weighed pads were then homogenized with a with the hydroxylase step carried out in acctate buffer of pH 4.0 (Behrens and Depocas 1975) and with the ['"G]synephrine extracted into ethyl acetate QNelson and Molinoff 1976). For blank determinations and wleasurernents with internal standards, tyrarnine was added only at the N-methyl transferase step as suggested by Fillenjr and West (1974).…”

Section: I$g~~/lren~et~r Qf Fisaue O L O O D J L~~jmentioning

confidence: 99%

Unilaterality of the sympathetic innervation of each pad of rat interscapular brown adipose tissue

Do¹,

Depocas²,

Zaror-Behrens³

1982

Can. J. Physiol. Pharmacol.

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The effects of sham, unilateral, and bilateral surgical denervation of rat interscapular brown adipose tissue (IBAT) on blood flow to the two IBAT pads of cold-acclimated (CA) rats during exposure of the animals to 22 or -6 degrees C and on the noradrenaline (NA) content and total dopamine beta-hydroxylase (DBH) (EC 1.14.17.1) activity of the pads in both warm-acclimated (WA)rats and CA rats were examined. Increase in IBAT blood flow upon cold exposure was taken as an index of sympathetically medicated calorigenesis in the tissue, and decreases in tissue levels of NA and DBH served as indices of the extent of destruction of the sympathetic innervation. At 24 h postsurgery, denervated pads of CA rats, rats, whether from unilaterally or bilaterally denervated IBAT, had less than 3% of the NA, 40-44% of the DBH, and 0% of the 10-fold, cold-induced increase in blood flow measured in intact pads of CA rats with sham-operated or unilaterally denervated IBAT. IBAT bilaterally denervated for 24 h was as responsive in terms of its maximum increase in blood flow during infusion of CA rats with NA as intact IBAT. DBH in denervated pads of both WA rats and CA rats fell to 5% or less of control levels at 2 days postdenervation and remained at these low levels, as did NA, for at least 8 weeks. These results strongly support the longstanding but recently challenged hypothesis that each pad of rat IBAT is independently innervated by sympathetic fibers.

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“…DOPAMINE-b-HYDROXYLASE (EC 1.14.17.1 ; DBH) activity in serum has been used as one measure of the function of the sympathetic nervous system in man and in experimental animals (WEINSHILBOUM & AXEL-ROD, 1971a). Dramatic changes in serum DBH activity occur during growth and development (WEIN- BEHRENS & DEPOCAS, 1975;OLUKOTUN et al, 1977). mental animals and man are to be interpreted correctly.…”

mentioning

confidence: 99%

“…mental animals and man are to be interpreted correctly. Rat serum DBH activity a t birth is several times higher than that in the blood of adult rats, increases to approx 5-7 times adult levels at 2 weeks of age and then drops sharply during the next 2-3 weeks (BEHRENS & DEPOCAS, 1975;OLUKOTUN et al, 1977). By way ofcontrast, human serum D B H activity is very low at birth, with levels comparable t o those found in the adult rat, and increases rapidly during the first years of life t o levels that are 1-2 orders of magnitude greater thap those found in adult rats (WEINSHILBOUM & AXELROD, 1971b;FREEDMAN et al, 1972;WEINSHILBOUM et al, 1978).…”

mentioning

confidence: 99%

Characterization of the Basis for Differences in Serum DBH Activity in Immature and Adult Rats by Use of Homologous Antibody

Grzanna

Nelson

Weinshilboum

et al. 1979

Journal of Neurochemistry

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Rat serum dopamine-8-hydroxylase (DBH) activity decreased 5-7-fold between 15 and 60 days of age. Immunoprecipitation performed with homologous antibody (guinea-pig anti-rat adrenal DBH) showed that during this time period the quantity of antibody necessary to precipitate 50% of the enzymatic activity (AD,,) decreased 5-fold from 0.25 to 0.05 pl/ml. The biochemical properties of rat serum DBH at 15 and 60 days of age were compared to test the hypothesis that there might be different biochemical forms of the enzyme in the blood of immature and adult rats. Thermal stability, apparent K, for tyramine, electrophoretic mobility, pH optima and elution profile on gel filtratioh chromatography were all found to be similar for rat serum DBH at both ages. On the basis of homospecific activity and multiple similarities in biochemical characteristics, it appears that differences in serum activity at the two ages reflect differences in the steady-state levels of enzyme.To determine the turnover of serum DBH in the two age groups, the recovery of enzyme activity was monitored after acute clearance of the circulating pool of DBH by treatment with the homologous antiserum. Immuno-titration of DBH activity in uiuo indicated that the total pool of serum enzyme was 4-fold greater in the mature rat than in 4-day-olds. After treatment of adult rats with 2pl of homologous antiserum, serum DBH activity was reduced by 85% with a half-life of recovery of 3.0 f 0.6 days; the estimated fractional rate of degradation was 0.23 f 0.06day-' and the rate of entrance was 2.3 f 0.2 units/ml/'day. After treatment of 4-day-old rats with 1 p1 of homologous antiserum, serum DBH activity was reduced by 95% with a half-life of recovery of 3.3 + 0.5 days: the estimated average fractional rate of degradation was 0.22 0.06day-' and the average rate of entrance was 10.7 & 1.6 units/ml/day. Thus, the several-fold difference in steady-state levels of serum DBH in rat pups as compared to adult rats appears to be due to greatly increased rates of entrance of the enzyme in the immature rats.

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Dopamine β-Hydroxylase in Rat Serum and Lymph: Changes with Age and Effect of Cold Exposure

Cited by 9 publications

References 10 publications

Effects of Aging on p‐ and m‐Octopamine, Catecholamines, and Their Metabolizing Enzymes in the Rat

Effects of Aging on p‐ and m‐Octopamine, Catecholamines, and Their Metabolizing Enzymes in the Rat

Unilaterality of the sympathetic innervation of each pad of rat interscapular brown adipose tissue

Characterization of the Basis for Differences in Serum DBH Activity in Immature and Adult Rats by Use of Homologous Antibody

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