Disease relevance of Metanephrine

• In the group of patients with congenital adrenal hyperplasia, plasma epinephrine and metanephrine concentrations and urinary epinephrine excretion were approximately 50 percent lower in those who had been hospitalized for adrenal crises than in those who had not [1].
• All patients with MEN-2 had high plasma concentrations of metanephrine, whereas the patients with von Hippel-Lindau disease had almost exclusively high plasma concentrations of only normetanephrine [2].
• The urinary metanephrine-to-creatinine ratio for the diagnosis of pheochromocytoma [3].
• Previously, we postulated that the unidentified pigment in the Dubin-Johnson syndrome results from the accumulation of tyrosine, phenylalanine and tryptophan metabolites, such as metanephrine, which are normally secreted in bile as organic anions [4].
• Metanephrine excretion was found to be quite constant throughout the day and night in ten patients with essential hypertension and seven patients with pheochromocytoma [5].

Psychiatry related information on Metanephrine

• To sum up, prefrontocortical dopamine depletion induces motor and emotional disturbances in rats and alters the neurochemical profile of the nucleus accumbens, not only inducing dopaminergic and noradrenergic hyperactivity but also leading to adrenaline and metanephrine excess [6].
• Thirty-four normal male subjects were tested to determine the relationships between physical fitness condition (Ismail criterion), levels of self-reported depression (MMPI) and anxiety (Welsh criterion), and the urinary concentrations of 3-methoxy-4-hydroxyphenylglycol (MHPG), normetanephrine (NM), and metanephrine (M) [7].

High impact information on Metanephrine

• The diagnosis of her tumor was delayed by a report of a falsely low urine metanephrine level, resulting from interference with the metanephrine assay by meglumine present in the urine because of contrast coronary angiography performed on the day of urine collection [8].
• We also noted a correlation between LOH on 1p and urinary excretion of metanephrine by these patients (P = 0.02) [9].
• Of the 38 patients without pheochromocytoma, 15 had high metanephrine levels but normal metanephrine-to-creatinine ratios [3].
• Thyroid function tests, antinuclear antibody tests and urinary vanillylmandelic acid and metanephrine levels were also obtained [10].
• For unipolar, but not bipolar, patients low CSF 5-HIAA and high urinary metanephrine values were associated with a greater incidence of drug response [11].

Chemical compound and disease context of Metanephrine

• OBJECTIVE: To compare the operating characteristics of two tests for diagnosing pheochromocytoma: 1) measurement of the ratio between urinary metanephrine and creatinine levels and 2) measurement of urinary metanephrine levels alone [3].
• Pheochromocytoma patients with or without diabetes did not differ in body mass index, plasma noradrenaline concentration, metanephrine excretion or tumor characteristics [12].
• Estimation of urinary catecholamines metanephrine and vanillylmandelic acid is routinely used in the biochemical detection of pheochromocytoma and in monitoring the completeness of tumor excision as well as the possibility of recurrence [13].
• Rabbits with a high glucose intake showed significantly higher weight gain (151 +/- 87 vs. 52 +/- 7 g, P = 0.01), water cumulative balance (542 +/- 132 vs. 411 +/- 87 ml; P = 0.02) and urinary metanephrine excretion (0.42 +/- 0.12 vs. 0.30 +/- 0.1 mumol/d, P = .03) [14].
• Metyrosine 1.5 g daily for days decreased 24-h urine metanephrine concentration by about 60% in a patient with multiple catecholamine-secreting paragangliomas [15].

Biological context of Metanephrine

• Complications were independently associated with preoperative systolic blood pressure [odds ratio (OR), 1.14/cm Hg], urinary metanephrine excretion (OR, 1.18/10 micromol x day), and with the number of operations (repeat vs. first operation OR, 5.36) [16].
• Plasma free metanephrine concentrations best predicted phenotype, with accuracy similar to that of genotype [17].
• Free and conjugated NMN, the latter after acid hydrolysis, were assayed using S-adenosylmethionine in the presence of phenylethanolamine-N-methyltransferase to form labeled metanephrine [18].
• Molecular genotype and plasma free metanephrine concentration predict phenotype with similar accuracy [17].
• Inhibition of Uptake2 with metanephrine (4 muM) prolonged by 20-40% the time taken for recovery of normal heart rate [19].

Anatomical context of Metanephrine

• We investigated the effect of stimuli activate the sympathetic nervous system on plasma catecholamines, renin activity, urinary metanephrine and normetanephrine, and various hemodynamic parameters in normal subjects (NIs) and borderline hypertensive (BH) subjects [20].
• Furthermore the nucleus accumbens contained higher levels of adrenaline and its transmethylated metabolite metanephrine [6].
• Epinephrine (200 micrograms base) was added at t = 0, and 200 min later, the mock cerebrospinal fluid was collected for metanephrine analysis [21].
• The alpha-adrenoceptor blocking agent, tolazoline, and the O-methylated metabolite of adrenaline, metanephrine, produced a concentration-dependent increase of tension in the smooth muscle of the cat isolated nictitating membrane [22].
• Differences between presynaptic and postsynaptic alpha-adrenoceptors in the isolated nictitating membrane of the cat: effects of metanephrine and tolazoline [22].

Associations of Metanephrine with other chemical compounds

• Thus, plasma metanephrine levels reflect adrenomedullary epinephrine content and, provided there is normal COMT activity, the adrenomedullary capacity to secrete epinephrine [23].
• Stepwise multiple regression analysis revealed that E was best predicted by pubertal stage and leptin, and MN by estradiol and leptin [24].
• We normalized values for urinary 24-h excretion of metanephrine, normetanephrine, and 3-methoxytyramine by dividing by an age- and sex-specific reference range [25].
• We describe a convenient and specific radioimmunoassay for urinary metanephrine, in which we used an antiserum generated in rabbits by injecting with synephrine conjugated to bovine serum albumin as described by Grota and Brown [Endocrinology 98, 615 (1976)] [26].
• Three properties of this propranolol metabolite lead to interference: (a) it is absorbed and eluted from ion-exchange resins under the conditions Pisano used for metanephrine isolation, (b) at high pH it absorbs at 350 to 360 nm, and (c) it is oxidized by periodate to a substance with negligible absorption in this region [27].

Gene context of Metanephrine

• Preoperative measurement of plasma free metanephrine and neck ultrasonography always should be done if the diagnosis of MTC is known preoperatively [28].
• COX-1(-/-) had a 89% reduction (P<0.0001) in the excretion of TxB2, a 76% reduction (P<0.01) in PGE2, a 40% reduction (P<0.0002) in 6-ketoPGF1alpha (6keto), a 27% reduction (P<0.02) in 11-betaPGF2alpha (11beta), a 35% reduction (P<0.01) in nitrate plus nitrite (NOx), and a 52% increase in metanephrine (P<0.02) [29].
• Children with TBI also showed a higher excretion of metanephrine in the resting situation in comparison to children with ADHD and controls [30].
• Total metanephrine values for most patients were appreciably lower than values obtained by the comparison procedure, that of Pisano (Clin. Chim. Acta 5: 406, 1970); however, results obtained by the two methods for two patients with pheochromocytomas agreed well [31].
• The significance of any difference in the free catecholamine or total metanephrine concentrations in the different groups was assessed by one-way ANOVA [32].

Analytical, diagnostic and therapeutic context of Metanephrine

• METHODS: Plasma metanephrine as well as plasma and urinary catecholamine concentrations were measured by high-performance liquid chromatography with electrochemical detection [33].
• Patients with fever and pheochromocytoma were significantly more likely to have a comorbid event, larger tumor, necrosis within the tumor, higher urinary metanephrine levels, longer duration of hospitalization prior to surgery, and to be non-white [34].
• To validate the clinical usefulness of this assay, we compared measurement of metanephrine by radioimmunoassay and of total urinary metanephrines by the Pisano colorimetric method [35].
• Comparison with a routine HPLC method (n = 192) by Deming regression yielded a slope of 1.00 +/- 0.02 microg/L, an intercept of -5.8 +/- 7.8 micro/L, and S(y/x) = 50.6 microg/L for metanephrine and a slope of 0.94 +/- 0.03, intercept of 19 +/- 11 microg/L, and S(y/x) = 60 microg/L for normetanephrine [36].
• Enzyme immunoassays based on microtiter plate technology have recently been developed for the quantitative determination of urinary metanephrine (M) and normetanephrine (NM) [37].

References