Catecholamines increase in the urine of non-segmental vitiligo especially during its active phase

Neural factors appear to play a major role in the pathogenesis of vitiligo. To investigate the possible correlation between vitiligo and peripheral monoaminergic system activity, we used high-pressure liquid chromatography and electrochemical detector methods to evaluate the basal urine excretion values of catecholamines [norepinephrine (NE), epinephrine and dopamine (DA)], their relative metabolites [3-methoxy-4-hydroxyphenylglycol (MHPG), normetanephrine (NMN), metanephrine (MN), vanilmandelic acid (VMA) and homovanillic acid], as well as 5-hydroxyindoleacetic acid (5-HIAA), in 35 healthy subjects and in 70 patients, suffering from non-segmental vitiligo at different stages of the disease. Levels of NE, DA, NMN, MN, MHPG, VMA and 5-HIAA were found to be significantly higher in patients than in controls. The patients with progressive vitiligo (n = 56) presented increased urinary excretion values for all parameters (in particular, NE levels) than other patients. Interestingly, in patients at its more recent vitiligo onset (<1 yr), NE values were different to those of subjects affected from 1 to 5 yr and from 6 to 10 yr. This result was confirmed by the significant negative relationship detected between NE excretion values and disease duration. In both vitiligo and control groups, significant correlations were found between monoamines as well as between these monoamines and their metabolites. The increase in catecholamine turnover, mainly occurring at the onset of the disease, is probably due to the stress associated with the appearance of lesions. Moreover, considering that these compounds readily produce toxic free-radicals and that vitiliginous subjects have a defective free radical defence mechanism, they may also contribute to the disappearance of melanocytes in the early phases of vitiligo.     

Catecholamine metabolism in children with Asperger’s and Kanner’s syndromes

In a stable state children with Asperger’s and Kanner’s syndromes demonstrate a similar decrease in plasma norepinephrine. In the aggravated state, these changes become more expressed and are characterized by a decrease in plasma tyrosine, norepinephrine, normetanephrine, and by an increase in dopamine and homovanillic acid and a decrease in excretion of norepinephrine and an increase in excretion of homovanillic acid, epinephrine and 3-methoxy-4-hydroxyphenylglycol (MHPG). In the aggravated state children with Kanner’s syndrome were characterized by increased plasma MHPG, decreased excretion of tyrosine and increased expression of normetanephrine. The observed imbalance in dopamine and epinephrine/norepinephrine systems suggests importance of combined analysis of changes in catecholamines and their metabolites as the most informative approach in the study of the effect of autistic disorders.     

Circulating antidiuretic hormone in the X-irradiated rat

Male rats exposed to 500 R of whole-body x-irradiation were allowed food and water ad libitum and housed in metabolism cages; water and food intake and urinary and fecal excretion were recorded daily. Urine output increased 200% during the first 24 hours after irradiation. No significant changes occurred in daily sodium, potassium, urea, or total solute excretion, although calcium excretion approximately doubled after irradiation. The marked increase in free water excretion implicates antidiuretic hormone (ADH) in this phenomenon. Application of a sensitive bioassay for ADH permitted measurement of plasma ADH concentrations in undisturbed, unanesthetized rats before and after irradiation. ADH levels were lower and frequently not detectable 24 hours after exposure. High ADH levels, however, could be provoked in irradiated rats by hemorrhage, indicating that the receptor cells and secretory ability of the posterior pituitary remained intact. Furthermore, irradiated rats responded normally to small intravenous injections (4 to 8 microU) of exogenous ADH. Rats with congenital diabetes insipidus given daily injections of Pitressin showed no postirradiation diuresis. Lastly, increased urinary calcium excretion may result from hypercalcemia which is known to induce diuresis through calcium-vasopressin antagonism. These results further suggest that the diuretic response is due to decreased circulating ADH.     

Effect of isradipine on urinary excretion of catecholamines and their metabolites in patients with pheochromocytoma]

An effect of calcium antagonist-isradipine-on catecholamines and their metabolites excretion with the urine in 4 patients with pheochromocytoma has been analysed. It was found that the excretion of OFFnoradrenaline and vanilaminomandelic acid is reduced. It may indicate inhibitory effect of calcium antagonists on catecholamines secretion in patients with pheochromocytoma.     

Development of Monoaminergic Neurotransmitters in Fetal and Postnatal Rat Brain: Analysis by HPLC with Electrochemical Detection

The monoamines dopamine, norepinephrine, epinephrine, and serotonin and their major metabolites 3,4-dihydroxyphenylacetic acid, homovanillic acid, 3-methoxy-4-hydroxyphenylethylene glycol, and 5-hydroxyindoleacetic acid were measured in the CNS of the rat during development from fetal day 18 to young adult. The catecholamines, serotonin, and their major metabolites remained low during fetal life. Concentrations measured in total brain started to increase around birth till the end of the fourth week of life after which steady-state levels were measured. Our results suggest that although monoamine systems are already morphologically well developed during late gestational life, they probably become a significant functional system only around birth and early postnatal life.     

Effects of226Ra and X-irradiation on the proliferative and differentiative ability of mouse hemopoietic stem cells

Summary The ability of hemopoietic stem cells to repopulate spleens of heavily irradiated syngeneic hosts in form of macroscopically visible clonal colonies of differentiating cells was studied in mice exposed for 32 and 4 weeks to internally deposited²²⁶Ra (0.56 and 0.46 µCi per mouse respectively) or to 100 rad X-irradiation. Exocolonizing test and cytological techniques were used for quantitative evaluation. The size of stem cell compartment was reduced and the function of the surviving stem cells was altered by radium and X-ray irradiation. The proliferation and maintenance of hemopoietic cell populations were found to depend not only on the numbers of stem cells but also on their multiplicative and differentiative capability.     

Urinary excretion of bioactive amines and their metabolites in psychiatric patients receiving phenelzine

Phenelzine [2-phenylethylhydrazine] (PLZ), a potent inhibitor of monoamine oxidase (MAO)-A and-B, is used widely in psychiatry. We have studied the effects of PLZ administration on urinary excretion of several bioactive amines and their metabolites in psychiatric patients. Urine samples (24-hour) were collected prior to treatment and again at 2 and 4 weeks of treatment with PLZ (30–90 mg daily in divided doses). Amines and metabolites analyzed included 2-phenylethylamine (PEA), m-and p-tyramine (m-and p-TA), phenylacetic acid (PAA), m-and p-hydroxyphenylacetic acid (m-and p-OH-PAA), tryptamine (T), 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), normetanephrine (NME), 3-methoxy-4-hydroxyphenylglycol (MHPG), 3-methoxytyramine (3-MT), and homovanillic acid (HVA). Levels of PEA, p-TA, 5-HT, and T were elevated during treatment with PLZ, but no significant changes in urinary excretion of the acid metabolites PAA, p-OH-PAA, and 5-HIAA were observed. Urinary levels of the noradrenaline metabolites NME and MHPG were increased and decreased, respectively; a similar pattern was observed with the dopamine metabolites 3-MT and HVA. There was an elevation in levels of m-TA and a decrease in its acid metabolite m-OH-PAA during the treatment with PLZ.     

INHIBITION OF RAT BRAIN PHENOL SULPHOTRANSFERASE IN VITRO BY NORADRENALINE and DOPAMINE METABOLITES1

Abstract— Kinetic parameters of the sulphotransferase reaction in rat brain were investigated in vitro at pH 7.4. Evidence is presented that the enzyme phenol sulphotransferase (EC 2.8.2.1) can be assayed with 4-methylumbelliferone or 3-methoxy-4-hydroxyphenylethyleneglycol as the substrate. Both assays give identical V_max values, whereas K_m values are 0.026 mm and 0.039 mm , respectively. Normetanephrine, metanephrine and the catecholamines adrenaline and dopamine, having a positive charge on the side chain at pH 7.4, do not inhibit 4-methylumbelliferone and 3-methoxy-4-hydroxyphenylethy-leneglycol sulphotransferase at this pH. Their deaminated metabolites 3,4-dihydroxyphenylethyleneglycol, 3,4-dihydroxymandelic acid, 3,4-dihydroxyphenylacetic acid, 3-methoxy-4-hydroxyphenylethylene glycol, 3-methoxy-4-hydroxyphenethanol and 3-methoxy-4-hydroxyphenylacetic acid inhibit both the enzyme activities. The type of inhibition is noncompetitive with the exception of 3-methoxy-4-hydroxy-phenylethyleneglycol, which is a competitive inhibitor of 4-methylumbelliferone sulphation. 3-Methoxy-4-hydroxy-mandelic acid does not inhibit the enzyme activities. It is concluded that the catecholamines themselves are not sulphated by rat brain in vitro at pH 7.4.     

Catecholamines Increase in the Urine of Non‐Segmental Vitiligo Especially During Its Active Phase

Neural factors appear to play a major role in the pathogenesis of vitiligo. To investigate the possible correlation between vitiligo and peripheral monoaminergic system activity, we used high‐pressure liquid chromatography and electrochemical detector methods to evaluate the basal urine excretion values of catecholamines [norepinephrine (NE), epinephrine and dopamine (DA)], their relative metabolites [3‐methoxy‐4‐hydroxyphenylglycol (MHPG), normetanephrine (NMN), metanephrine (MN), vanilmandelic acid (VMA) and homovanillic acid], as well as 5‐hydroxyindoleacetic acid (5‐HIAA), in 35 healthy subjects and in 70 patients, suffering from non‐segmental vitiligo at different stages of the disease. Levels of NE, DA, NMN, MN, MHPG, VMA and 5‐HIAA were found to be significantly higher in patients than in controls. The patients with progressive vitiligo (n = 56) presented increased urinary excretion values for all parameters (in particular, NE levels) than other patients. Interestingly, in patients at its more recent vitiligo onset (<1 yr), NE values were different to those of subjects affected from 1 to 5 yr and from 6 to 10 yr. This result was confirmed by the significant negative relationship detected between NE excretion values and disease duration. In both vitiligo and control groups, significant correlations were found between monoamines as well as between these monoamines and their metabolites. The increase in catecholamine turnover, mainly occurring at the onset of the disease, is probably due to the stress associated with the appearance of lesions. Moreover, considering that these compounds readily produce toxic free‐radicals and that vitiliginous subjects have a defective free radical defence mechanism, they may also contribute to the disappearance of melanocytes in the early phases of vitiligo.     

Suppression of norepinephrine secretion by dopamine in children with neuroblastoma: evidence for precursor inhibition in catecholamine pathway

To elucidate catecholamine (CA) secretory dynamics in neuroblastoma, urinary excretion of CAs and their metabolites was serially measured in 6 patients aged 3 months to 3 years before and during treatment. After tumor extirpation, increased urinary CAs were promptly normalized; the reduction reflected the amount of CA production from the tumor. Urinary dopamine (DA) showed the most prominent reduction, whereas DA content in the tumor was very small, indicating that the DA produced was immediately released from the tumor and metabolized in extra-tumor tissues. In contrast, patients receiving chemotherapy continued to excrete excess DA and homovanillic acid (HVA), which were increased further at recidivation. One patient showed an inverse correlation between DA and norepinephrine (NE) excretion; a decrease in DA was associated with an increase in NE and plasma DA-beta-hydroxylase (DBH) activity. A similar inverse correlation was also noted between NE and vanillylmandelic acid (VMA) or 3-methoxy-4-hydroxyphenylglycol (MHPG) excretion, while HVA and dihydroxyphenylacetic acid (DOPAC) were positively correlated with DA excretion. Urinary HVA and VMA were lineally correlated but in a patient excreting an enormous amount of DA, urinary VMA was markedly suppressed in terms of HVA excretion. Excessive DA induced an increase in renal water output but did not enhance Na and K excretion. These results indicate that endogenous DA overload in neuroblastoma inhibits NE production by suppressing DBH activity as well as by forming VMA and MHPG. This precursor regulation appears to be the characteristic of the CA metabolic pathway.     

Adrenomedullary Secretion of DOPA, Catecholamines, Catechol Metabolites, and Neuropeptides

Abstract: Catecholamines and their metabolites have been proposed as markers of sympathetic nervous system stimulation. However, the adrenal medulla is a rich source of catecholamines and catecholamine metabolites and may play a significant role in plasma levels of these compounds. In addition to adrenal catecholamine metabolite efflux, the role of the catecholamine precursor 3,4-dihydroxyphenylalanine (DOPA) has not been fully evaluated. The simultaneous effluxes of catecholamines, metabolites, DOPA, and neuropeptides were measured in perfusates from isolated dog adrenals. The relative abundance of compounds detected consistently during unstimulated conditions was epinephrine ≫ norepinephrine > 3,4-dihydroxyphenylglycol > metanephrine > normetanephrine > dopamine > 3,4-dihydroxyphenylacetic acid > 3-methoxy-4-hydroxyphenylglycol ≥ DOPA ≫ [Met]enkephalin ≫ neuropeptide Y. Effluxes of analytes were not affected by cocaine and the ratios of catecholamines to metabolites increased dramatically with carbachol stimulation, consistent with negligible reuptake into adrenal cells. Thus, most of the 3,4-dihydroxyphenylglycol is expected to be derived from epinephrine and norepinephrine subsequent to translocation from chromaffin vesicles into the cytosol. The efflux of DOPA increased dramatically during stimulation with 30 µ M carbachol in a calcium-dependent manner. Efflux of DOPA during the initial stabilization period of the perfusion preparation declined exponentially, in parallel with the effluxes of the catecholamines and neuropeptides but not with metabolites. Evoked release of DOPA was Ca²⁺-dependent. These data suggest that DOPA can be stored and released exocytotically from chromaffin granules.     

Unexpected changes in urinary catecholamines and vanillylmandelic acid following rape assault

Although psychological changes are recognized to occur in rape assault survivors there is no information on the biochemical changes in these victims. This study compares urinary catecholamines and metabolites in 17 rape victims to two female control groups (one of which engaged in normal sexual intercourse and the other did not). We found, in the rape victims, unexpected changes in the excretion pattern of catecholamines and metabolites as compared to the various control groups. The most significant difference was the dramatic increase in urinary conjugated dopamine (P less than 0.01) in the rape victims which remained elevated for over 24 hr. Urinary vanillylmandelic acid (VMA) rose significantly in rape assault victims when compared to the normal control group. The VMA levels in rape victims were significantly lower, however, than in the women who had undergone (normal) sexual intercourse (P less than 0.01). Urinary free epinephrine showed a marked decline and remained depressed for over 24 hr in the rape assault victims (P less than 0.01) compared to normal controls. Some possible reasons for these patterns in catecholamines and metabolite excretion are suggested. These changes may be of importance in the poststress syndrome that occurs following the rape assault. In summary, a different profile of catecholamine and metabolite excretion patterns was found in rape compared to normal sexual intercourse. The enhanced dopamine excretion is contrary to the expected change of enhanced epinephrine secretion in severe stress.     

Development of resistance to coccidiosis in the absence of merogonic development using X-irradiated Eimeria acervulina oocysts

Sporulated oocysts of the protozoan Eimeria acervulina were subjected to 0, 10, 15, 20, or 30 krad of X-irradiation and inoculated into susceptible outbred chickens to determine if radioattenuated coccidia could induce protection against parasite challenge. Irradiation treatment had an appreciable dose-dependent effect on parasite development. Insignificant numbers of oocysts were produced by chickens inoculated with parasites that had been exposed to greater than 10 krad X-irradiation. Sporozoites exposed to 15 or 20 krad irradiation conferred significant protection against the appearance of intestinal lesions after parasite challenge. Sporozoites subjected to the highest dose level (30 krad) did not produce any significant level of protection. To investigate this phenomenon further and assess intracellular parasite development, susceptible outbred strains of chickens were administered either nonirradiated (0 krad) oocysts or oocysts that were exposed to an optimal dose (15 krad) or a high dose (30 krad) of X-irradiation. Immunofluorescence staining of tissue sections from each treatment group at various intervals after the initial administration of irradiated parasites indicated that sporozoites exposed to 15 krad irradiation were as capable of invading the host intestinal epithelium as nonirradiated sporozoites. However, at 48, 60, 72, and 96 hr, there was a marked reduction in merogonic development in groups receiving irradiated sporozoites compared to those inoculated with nonirradiated parasites. The latter parasites underwent profuse merogonic development; in contrast, irradiated parasites demonstrated little (15 krad) or no (30 krad) merogonic development. These results suggest that induction of a protective immune response occurs during a critical period early in intracellular development of E. acervulina.     

Phenol sulphotransferase: purification and characterization of the rat kidney and stomach enzymes

3'-Phosphoadenosine-5'-phosphosulphate-dependent enzymes that catalyse sulphation of p-nitrophenol have been purified from rat kidney and stomach mucosa by affinity chromatography on the p-hydroxyphenylacetic acid-agarose conjugate, by chromatography on DEAE-cellulose and Sephadex G-100. The phenol sulphotransferase (PST) from rat kidney had Mr of 69 000 and that of the stomach enzyme was 32 000. With p-nitrophenol as the sulphate acceptor, the pH optima were 6.4 for the stomach PST and 5.4 and 6.6 for the kidney enzyme. Both enzymes were inhibited by 2,6-dichloro-4-nitrophenol and phenylglyoxal, an arginine specific modifying reagent. Both enzymes readily sulphated p-nitrophenol, 2-naphthol, 1-naphthol and salicylamide and did not act on biogenic amines (e.g. epinephrine, norepinephrine, dopamine, serotonin), acid metabolites of catecholamines (e.g. 3,4-dihydroxyphenylacetic acid, homovanillic acid), and O-methylated metabolites of catecholamines. Only the stomach enzyme sulphated such catecholamine metabolites as homovanillic alcohol and 3-methoxy-4-hydroxyphenylglycol. In contrast to the brain enzyme, but similarly to the liver enzyme, the kidney and stomach phenol sulphotransferases appear to sulphate exogenous phenolic substrates in preference to potential endogenous substrates.     

Catecholamine metabolites in human plasma as indices of brain function: Effects of debrisoquin

Metabolites of catecholamine neurotransmitters in plasma are, potentially, an easily available indicator of brain function in man. The peripheral contribution to these metabolites was lowered by debrisoquin sulfate, a monoamine oxidase inhibitor that does not enter the brain. In the monkey, it had been shown that debrisoquin decreased peripheral production of the dopamine metabolite, homovanillic acid (HVA), without changing production by brain; production of the norepinephrine metabolite, 3-methoxy-4-hydroxyphenethyleneglycol (MHPG) was decreased peripherally and in brain. Low-dose debrisoquin administration in man eliminated about 80% of the peripheral contribution to HVA and MHPG in plasma, resulting in a situation in which at least 75% of these metabolites in plasma were from the brain. Under these conditions, HVA and MHPG in plasma had a significant correlation. It could also be estimated that production of MHPG by brain was reduced 55%. Debrisoquin potentially provides a method for studying brain catecholamines through their metabolites in plasma and for treating conditions of brain noradrenergic excess.     

CATECHOLAMINE METABOLISM IN THE DOG: COMPARISON OF INTRAVENOUSLY AND INTRAVENTRICULARLY ADMINISTERED [14C]DOPAMINE AND [3H]NOREPINEPHRINE

—The urinary excretion of labelled metabolites was measured in dogs which had been injected intravenously or intraventricularly with [³H]norepinephrine or [¹⁴C]dopamine. [³H]Norepinephrine injected by either route produced more labelled 3-methoxy-4-hydroxy-phenylglycol than 3-methoxy-4-hydroxymandelic acid, as did [¹⁴C]dopamine after intravenous administration. In contrast, following the intraventricular injection of [¹⁴C]dopamine, more [¹⁴C]3-methoxy-4-hydroxymandelic acid was formed than [¹⁴C]3-methoxy-4-hydroxyphenylglycol. These observations suggest that the metabolism of exogenously-administered and endogenously-formed norepinephrine may proceed through different routes and that the predominant metabolite of norepinephrine in canine brain may be 3-methoxy-4-hydroxymandelic acid rather than 3-methoxy-4-hydroxyphenylglycol.     

Lack of synergistic effect between X-ray and UV irradiation on the frequency of chromosome aberrations in PHA-stimulated human lymphocytes in the G1 stage.

PHA-stimulated human lymphocytes in the G1 stage were irradiated with UV radiation and X-rays, and the cells were analyzed for chromosomal aberrations in the first mitotic division. The frequency of dicentric chromosomes after single X-irradiation in the G1 stage was about twice the yield in the G0 stage. No increase in the yield of dicentrics was observed after combined irradiation with UV and X-rays. This is contrary to the finding for G0 lymphocytes, where a 2-fold increase of chromosome aberrations was observed. UV irradiation of G1 lymphocytes induced chromatid-type aberrations whereas no significant yield of dicentric chromosomes was observed. This is in agreement with previous findings in Chinese hamster cells in the G1 stage [7]. Irradiation of G0 lymphocytes with UV radiation induce a low frequency of dicentric chromosomes. Thus, the present data indicate that the ratio between chromosome-type and chromatid-type aberrations is different in the G1 and G0 stages in human lymphocytes irradiated with UV radiation.     

Regional release of cyclooxygenase products after radiation exposure of the rat

The present study evaluated the regional release of cyclooxygenase products 4 h following 20 Gy gamma irradiation. Thoracic shielding reduced the radiation-induced increase in immunoreactive thromboxane B2 (iTxB2) excretion to control levels while abdominal shielding partially attenuated the altered excretion of this cyclooxygenase product. To assess the role the kidneys play in the radiation-induced increase in iTxB2 excretion, an in situ isolated perfused rat kidney model was developed. The excretion rate of iTxB2 from irradiated isolated perfused kidneys was not significantly different from sham-irradiated perfused kidneys. Radiation exposure did alter renal cyclooxygenase product release in that the excretion of immunoreactive prostaglandin E2 (iPG2) and immunoreactive 6-keto-PGF1 alpha was significantly increased (P less than 0.05) in irradiated isolated perfused kidneys. These data show that radiation-induced increases in iTxB2 excretion are primarily due to altered extrarenal synthesis and/or metabolism of this arachidonate metabolite.     

Plasma catecholamines and urinary excretion of their main metabolites in three models of portal hypertension

We have measured, by a specific radioenzymoassay, the plasma concentration of dopamine (DA) and norepinephrine (NE) and by gas chromatography the urinary excretion of some catecholamine metabolites (HVA, homovanillic acid, DOPAC, dihydroxyphenyl acetic acid; VMA, vanilmandelic acid, and DOPEG, dihydroxyphenyl glycol) in three groups of rats with portal hypertension: cirrhotic rats (CR), rats with progressive portal hypertension (PPH) and rats with progressive hepatic congestion (PHC). The three groups of rats had portal hypertension. PPH and PHC had also intrahepatic hypertension. CR rats showed an increased urinary excretion of NE and DA metabolites with a normal plasma concentration of these catecholamines, suggesting an increased turnover of NE and DA in this experimental model. PPH animals had a high plasma DA concentration with a decreased urinary excretion of catecholamine metabolites. PHC showed high plasma DA and NE levels with normal or increased urinary excretion of its metabolites. These results suggest that an increased neural activity is present in the early stages of experimental cirrhosis in rats and this alteration does not seem directly related to the portal hypertension but perhaps to the intrahepatic hypertension or to the hepatocellular damage.