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Glucose intolerance is often observed in patients with pheochromocytoma. However, it remains controversial issue that glucose intolerance on pheochromocytoma is caused by impaired insulin secretion and/or by increased insulin resistance. We aimed to reveal the mechanism of glucose intolerance on pheochromocytoma with regard to the type and amount of catecholamines released. We evaluated 12 individuals diagnosed with pheochromocytoma and who underwent surgery to remove it. We examined glycemic parameters before and after surgery and investigated the association between the change of parameters of insulin secretion (homeostasis model assessment of β-cell function (HOMA-β)), insulin resistance (homeostasis model assessment of insulin resistance (HOMA-IR)) and that of urinary levels of metanephrine/normetanephrine before and after surgery. Overall, fasting plasma glucose, glycated hemoglobin (HbA1c), HOMA-β, and HOMA-IR were improved significantly after surgery. Regression analysis showed that the improvement in HOMA-β from before to after surgery was significantly positively associated with an improvement in urinary levels of metanephrine from before to after surgery and showed a significantly negative association with improvement in urinary levels of normetanephrine from before to after surgery. The improvement in HOMA-IR from before to after surgery was significantly positively associated with an improvement in urinary levels of normetanephrine from before to after surgery. Our results showed that pheochromocytoma extirpation improved glycemic parameters. Furthermore, the different effects elicited by excess amounts of adrenaline and noradrenaline on glucose intolerance were demonstrated.

The article considers the technique of simultaneous detection of free catecholamines and free metanephrines in urine using inverse phase highly effective liquid chromatography with fluorimetric detection. The solid phase extraction was implemented on cartridges with 30 mg of hyper cross-linked polystyrene (Purosep-200). The simplicity, reproducibility and sufficient sensitivity of technique permit applying it in clinical practice to diagnose pheochromocytoma.

The silica monolith with ionizable silanol groups and large surface area was found able to function as an offline cation exchange solid phase extraction (SPE) cartridge for extracting polar analytes. The prepared cartridge was housed in a 2-mL syringe fixed over a SPE vacuum manifold. The unique property of this silica monolithic cartridge was demonstrated by extracting epinephrine, normetanephrine and metanephrine from urine samples. These analytes were chosen as model compounds for testing because of their high hydrophilicity, and being candidates monitored for clinical diagnosis. The extracted analytes, after concentration and reconstitution were then quantitated by high-performance liquid chromatography coupled to mass spectrometer (HPLC/ESI/MS). Multiple reactions monitoring was carried out with transitions: 184-->107, 184-->134 and 198-->148 for analyzing epinephrine, normetanephrine and metanephrine, respectively. The limit of detection was 3 ng/mL for metanephrine and 5 ng/mL for normetanephrine and epinephrine. The relative standard deviations of measurements ranged from 2 to 10%. The sorbent offered good linearity with coefficient of determination (r(2))>0.99, over a concentration range of 20-200 ng/mL. The relative recoveries ranged from 60 to 67%, 55 to 59% and 99 to 105% for epinephrine, normetanephrine and metanephrine, respectively. The prepared cartridge had shown potential and was found robust in extracting the polar analytes repeatedly without any significant loss in efficiency., (Copyright 2010 Elsevier B.V. All rights reserved.)

Guillain-Barré syndrome is an acute demyelinating polyradiculoneuritis usually evolving with rapid, functional recovery. In severely paralysed patients, cranial nerve palsy and autonomic nervous system dysfunctions are common. Lesions of the spinal roots predominate but segmentary demyelination of peripheral nervous system reflects various clinical subtypes. Twelve patients (42,8 p. cent) had clinical dysautonomia. Ten had an increase of urinary methoxylated metabolites. Patients exempt of dysautonomia had normal biological parameters. The elevated level of urinary methoxylated metabolites is statistically correlated to clinical dysautonomia and can be used as a biological marker to monitoring demyelinating polyradiculoneuritis.

This study investigated the relationship between biological and psychological processes in the recovery phase of depression during treatment with cognitive therapy. In particular, we tested the hypothesis that biological and psychological processes are independent; the hypothesis that they are related in a linear or sequential process; and the hypothesis that there is a circular relationship between them. 35 depressed patients completed a 12 week program of cognitive therapy. Changes in measures of negative thinking and amine dysfunction over the course of therapy were compared for those who improved and those who did not. There was a significant relationship between improvement in symptoms and change for ATQ scores, DAS scores, and epinephrine levels. There was significant change in metanephrine levels during therapy which was not related to improvement. The changes were not consistent across indices. Although the results did not provide definite support for any of the four models of the relationship between biological and psychological variables during recovery from depression, the finding that there was some change in some of the indices of amine dysfunction during cognitive therapy indicates that the interface between biological and psychological processes in depression should continue to be studied.

The detection and diagnosis of pheochromocytoma are highly dependent on the biochemical confirmation of excessive catecholamine release by the tumor. As the reliability of baseline plasma catecholamines in the detection of pheochromocytoma is questionable, assessment of the excretion rates of catecholamines or metabolites in 24-h urine collections remains the mainstay of initial biochemical investigation. However, diagnostic difficulties can arise from incomplete collection of 24-h specimens or equivocal increases in catecholamines due to stress. To investigate the diagnostic validity of shorter collection times for the biochemical detection of this tumor, we measured the excretion of catecholamines and metabolites after sleep, a period associated with decreased sympathetic activity. Overnight catecholamines, metanephrines, and 4-hydroxy-3-methoxymandelic acid (HMMA) levels were measured in 16 patients with histologically confirmed pheochromocytomas, 166 patients with hypertension, and 24 normotensive subjects. All measurements were performed by high performance liquid chromatography with electrochemical detection. Overnight excretion of norepinephrine in the tumor group (range, 86-1552 nmol/mmol creatinine) was significantly different (P <0.001) from that in the nontumor group (14-63 nmol/mmol creatinine). Autonomous secretion of norepinephrine was evident in all urine collections, including a patient with a predominantly epinephrine-secreting tumor. Overnight normetanephrine levels displayed a similar excretion pattern (P < 0.001), whereas overnight epinephrine and metanephrine levels were normal in 10 of the 16 patients with pheochromocytoma. In contrast, HMMA excretion in overnight urine collections was highly variable, with only 6 of the 16 patients in the tumor group having consistently elevated excretion. In the other 10 patients, overnight HMMA excretion showed a high intravariability. The measurement of catecholamines and total metanephrines after sleep is a viable approach for the exclusion of pheochromocytoma, as overnight urine collections completely differentiated patients with pheochromocytoma from hypertensive patients. Compared to 24-h results, overnight urinary norepinephrine levels provided a better diagnostic sensitivity and specificity (100% sensitivity and 98% specificity compared with 88% and 82%). Sleep urine samples simplify the collection protocol while avoiding the effects of stress and exercise.

Assays of urinary catecholamines and their metabolites (HVA, VMA, dopamine) permit biochemical diagnosis of neuroblastoma in approximately 80% of patients. The urinary methylated catecholamine metabolites normetanephrine (NMN), metanephrine (MN), and 3-methoxytyramine (3-MT) were analyzed in 18 patients with neuroblastoma and compared with reference values established for 69 healthy pediatric controls. All 18 neuroblastoma patients had raised urinary excretion of at least one of the three commonly assayed metabolites (HVA, VMA, dopamine). Similarly, raised urinary excretion of a methylated metabolite was noted in all but one of the neuroblastoma patients. The 3-MT level was pathologic in 16 of the 18 patients (89%). In this series, 3-MT assay sensitivity was sufficient to warrant trials on a larger population including comparison with patients considered nonsecretors by routine assay procedures.

In this relatively simple procedure for extracting metanephrines from urine, after an internal standard (4-hydroxy-3-methoxybenzylamine in 1 mmol/L HCl) is added, the sample is hydrolyzed in a boiling water bath, then treated with ammonia and alumina. Excess ammonia is removed under reduced pressure and the sample is applied to a 1-mL Bond Elut SCX column, which is washed, and metanephrines and internal standard are eluted with 0.5 mmol/L sodium acetate/acetonitrile (3/1 by vol). Of this elute, 5 microL is injected into a 15 cm x 4.6 mm (i.d.) column packed with 5-microns octadecylsilyl silica particles, which is eluted with a mobile phase containing tetramethylammonium perchlorate. Peaks are detected coulometrically at +0.28 V. In the resulting chromatogram, metanephrines give sharp peaks, well resolved from peaks for solvent and internal standard. There are no extraneous peaks for catechols or mono-oxygenated phenylethylamines. Results correlated well (r = 0.999, n = 13) with those by earlier described liquid-chromatography.

Sixty-four patients with pheochromocytoma were operated upon at Sahlgrenska Hospital during 1956-82. The excretion of adrenaline and/or noradrenaline as well as their metabolites was high at each observation in 28 subjects with sustained hypertension, one patient, however, showing only slightly increased excretion of adrenaline at one observation. Another of the hypertensive patients consistently displayed normal amounts of vanilmandelic acid and metanephrines. Most of 28 patients with paroxysmal hypertension showed similar results. In five subjects with few attacks, however, normal findings were obtained on one or several occasions. Among the remaining patients the excretion of catecholamines was normal in the face of severe hypertension in two, the high blood pressure being probably due to diseases other than pheochromocytoma. Five normotensive subjects without hypertensive attacks presented variable findings. The results from analyses of catecholamines were somewhat more helpful than those from measurements of vanilmandelic acid, which failed completely in one hypertensive patient and in three others with paroxysmal attacks.

The activity of the sympathetic adrenal system in cosmonauts exposed to a stay in space lasting for about half a year has so far been studied only by measuring catecholamine levels in plasma and urine samples taken before space flight and after landing. The device "Plasma 01", specially designed for collecting and processing venous blood from subjects during space flight on board the station Salyut-7 rendered it possible for the first time to collect and freeze samples of blood from cosmonauts in the course of a long-term 237-day space flight. A physician-cosmonaut collected samples of blood and urine from two cosmonauts over the period of days 217-219 of their stay in space. The samples were transported to Earth frozen. As indicators of the sympathetic adrenal system activity, plasma and urine concentrations of epinephrine and norepinephrine as well as urine levels of the catecholamine metabolites metanephrine, normetanephrine, and vanillylmandelic acid were determined before, during and after space flight. On days 217-219 of space flight plasma epinephrine and norepinephrine levels were slightly increased, yet not substantially different from normal. During stress situations plasma norepinephrine and epinephrine levels usually exhibit a manifold increase. On days 217-219 of space flight norepinephrine and epinephrine levels in urine were comparable with pre-flight values and the levels of their metabolites were even significantly decreased. All the parameters studied, particularly plasma norepinephrine as well as urine norepinephrine, normetanephrine, and vanillylmandelic acid, reached the highest values 8 days after landing. The results obtained suggest that, in the period of days 217-219 of the cosmonauts stay in space in the state of weightlessness, the sympathetic adrenal system is either not activated at all or there is but a slight activation induced by specific activities of the cosmonauts, whereas in the process of re-adaptation after space flight on Earth this system is considerably more markedly activated.

Results of 1414 measurements of urinary excretion of free and conjugated (total) metanephrine and normetanephrine (total metanephrines, tMN) and of 1630 measurements of vanilmandelic acid (VMA) excretion were analysed according to the month of sample collection. These collections had been carried out as a part of a study of hypertension at out institute over the 5-year period between 1970 and 1975. The means and scatters of tMN were significantly varied depending on the season of the year; the mean during 3 months of summer was 380 mug/day and the mean for 3 winter months 800 mug/day. The scatter of tMN in winter months was wider. A minor seasonal variation was observed for VMA: the means of summer and winter months were 3.8 mg/day and 4.5 mg/day, respectively. The results suggest a seasonal difference of catecholamine catabolism.

Hydrolyzed urine with added ring-trideuterated normetanephrine and metanephrine is applied to wet C18-reversed-phase minicolumns. The "metanephrines" are eluted, dried, derivatized with pentafluoropropionic anhydride, and analyzed with the gas chromatograph-mass spectrometer. Ions for the nondeuterated and trideuterated compounds are monitored at ml z 458 and 461, respectively. For both normetanephrine and metanephrine, the standard curve is linear over the range 10-2000 micrograms/L and the procedure has adequate precision both within-run (CV less than 3%) and between-day (CV less than 7%). Alkaline pH in the extraction is important for optimal analytical recovery. We have examined the potential value of untimed urine specimens for screening purposes and compared 24-h urine concentrations of these analyses in normotensive and hypertensive persons.

The authors studied the excretion of 3-methoxy-4-hydroxyphenyl glycol (MHPG), normetanephrine (NM), metanephrine, and homovanillic acid in 7 hyperactive and 12 control children. MHPG was lower but NM was significantly higher in hyperactive children than in controls. Administration of d-amphetamine for 2 weeks depressed the levels of MHPG, NM, and metanephrine. The authors suggest a decreased central norepinephrine activity, which may be secondary to the interruption of norepinephrine fibers in the medial forebrain bundle.

A sensitive and specific direct analysis of urinary normetanephrine (NMN) and metanephrine (MN) was achieved utilizing reversed-phase high performance liquid chromatography and electrochemical detection. Individual specimens from "control" subjects and those with pheochromocytoma were hydrolyzed and the metanephrines separated from other urinary constituents by elution with ammonia from a Dowex CG-50 resin. Chromatographic peaks were identified by retention behavior, co-chromatography with reference compounds, ratio of responses at various oxidation potentials and stopped-flow UV spectra of the collected fractions. The NMN and MN content for the control subjects was between 0.086 and 0.21 (mean - 0.14) microgram/mg creatinine and 0.012 and 0.092 (mean = 0.039) microgram/mg creatinine, respectively. The values for subjects with pheochromocytoma varied from 1.5 to 27.5 (mean = 9.9) microgram/mg creatinine for NMN and 0.10 to 1.60 (mean = 0.86) microgram/mg creatine for MN. The patient with ganglioneuroma had an NMN of 4.1 and an MN of 0.80 microgram/mg creatinine. While this method permits discrimination between those patients with pheochromocytoma and the overwhelming majority of hypertensive patients, it may ultimately be further extended to separate normal subjects from those with more subtle derangements in catecholamine metabolism.

A simple method for the simultaneous analysis of normetanephrine, metanephrine and 3-methoxytyramine (both free and conjugated) in human urine by reversed-phase ion-pair high-performance liquid chromatography with electrochemical detection has been developed. Existing methods have been optimized for extraction by study of analytical parameters. The hydrolysed urines are purified and concentrated by successive passages on two ion-exchange resins and ammoniacal elution to eliminate interference from pigments or related chemical compounds. The methoxyamines are separated by high-performance liquid chromatography on a reversed-phase column. Detection and quantitation are achieved with an electrochemical detector using a vitreous carbon electrode. Samples can be injected at 25-min intervals. Reference values of adults and children are given.

The urinary excretion of vanillylmandelic acid (VMA), homovanillic acid (HVA) and total metanephrines (TMNs) was studied in a group of White male alcoholic patients under three experimental conditions--on admission and prior to treatment, after 7 days of administration of a placebo, and after 9 days of administration of disulfiram 400 mg/d Disulfiram caused a significant decrease in VMA levels compared with the pretreatment (P less than 0,01) and placebo (P less than 0,05) levels. The output of HVA and TMNs was unchanged. It is suggested that disulfiram may produce false-negative results in cases of suspected phaeochromocytoma if VMA levels only are assayed. TMNs would appear to be the measurement of choice in such a situation.

Urine after the addition of phenylephrine as internal standard is hydrolyzed and passed through a disposable BondElut SCX column. After washing the column, metanephrines and the internal standard are eluted with dilute ammonia. The eluate is treated with periodate and extracted with toluene. The toluene layer is collected and phenols are extracted into dilute tetramethylammonium hydroxide. An aliquot of the aqueous layer is chromatographed on a nonsilica resin base reversed phase column with an alkaline mobile phase. The peaks are detected by an absorbance detector at 350 nm. There is a baseline separation of vanillin formed by metanephrines and of m-hydroxybenzaldehyde formed by phenylephrine. The procedure is linear from 0.2 mg to 10 mg of metanephrine per liter of urine. The procedure has a high degree of specificity as the commonly prescribed antihypertensive drugs and their metabolites do not interfere.

Twenty-four men, mean age 63 +/- 1.7 years, with systemic systolic hypertension were studied before and after 1 month of therapy with oral hydrochlorothiazide, 50 mg/day. The control mean plasma volume was 2,664 +/- 96 ml, cardiac index 3.9 +/- 0.2 liters/min/m2, stroke volume index 52 +/- 2 ml/beat/m2, systemic vascular resistance 1,351 +/- 80 dynes s cm-5, plasma aldosterone 8.6 +/- 1.0 ng/dl and 24-hour urinary excretion of metanephrines 0.371 +/- 0.044 mg. On renin-sodium profiling in 23 patients, 12 were classified into a normal group and 11 into a low-renin group; none had high renin values. Based on multiple regression analysis, the 24-hour urinary excretion of total metanephrines appeared to be the single most important factor explaining 28% of the variability in systolic blood pressure (BP). After therapy with oral hydrochlorothiazide, the elevated systolic BP decreased (p less than 0.0001) and diastolic BP decreased (p less than 0.005), with concomitant reduction in systemic vascular resistance (p less than 0.03). Patients in both the normal- and low-renin groups had normal plasma volume and responded similarly to thiazide diuretic therapy, without symptomatic side effects.

Uniform liquid-chromatographic conditions were developed such that we could quantify norepinephrine, epinephrine, normetanephrine, metanephrine, vanillylmandelic acid, and 5-hydroxyindoleacetic acid in urine by using a single mobile phase of monochloroacetic acid and citric acid, 0.1 mol/L each. All compounds were separated on a C18 column and detected electrochemically at a potential of +0.800 V. Optimization of these uniform chromatographic conditions significantly shortens the changeover time required from one assay to another, resulting in a substantial savings of time and cost to the laboratory.

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)]. The antiserum is specific for metanephrine and epinephrine. Epinephrine cross reaction is minimized to 1% by adding 2 ng of epinephrine to each assay tube. Incubation time is 12 h. The sensitivity of the assay is 40 pg. Within-and between-assay coefficients of variation are 7.0 and 9.7%, respectively. We assayed first-voided morning urine and 24-h urine specimens from 15 normal subjects before and after acid hydrolysis, to assess total and free metanephrine concentrations. Mean (+/-SD) total and free urinary metanephrine excretion were 17 +/- 11 and 3.5 +/- 1.0 micrograms/24 h in these subjects; corresponding values for the morning specimens were 13.4 +/- 8.3 and 3.5 +/- 1.5 micrograms/liter, respectively.

The influence of 35 commonly used drugs on measurement of metanephrines in urine was evaluated. Two concentrations of drugs were chosen for study based on usual doses and the percent of dose excreted unchanged in the urine. At "medium" drug concentrations, only phenylephrine falsely elevated metanephrine levels, whereas at a 10-fold higher drug concentration, guanethidine, hydrocortisone, imipramine, isoetharine, levodopa, phenobarbital, and phenylephrine caused positive interference. Propranolol and theophylline caused a negative interference at the two concentrations studied. The significance of these results is discussed.

A radioimmunoassay involving an 125I ligand has been developed and applied to the measurement of urinary metanephrine. 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. The radioimmunoassay is specific for metanephrine, whereas the colorimetric method measures both metanephrine and normetanephrine. We used both methods to determine urinary metanephrine or total metanephrines in subjects with essential hypertension, pheochromocytoma, the syndrome of multiple endocrine adenomatosis type 2, and normotensive volunteers. The mean and upper limit of normal (3 SD) for metanephrine by radioimmunoassay in our normotensive volunteers was 94.2 microgram/24 h and 229 microgram/24 h, respectively, which compares well with reported values of 87.6 microgram/24 h and 319 microgram/24 h by non-radioimmunoassay methods. Both radioimmunoassay and colorimetry accurately identified five patients with known pheochromocytoma. Good correlation (r = 0.993) was demonstrated between the two assays in a comparison of patients with essential hypertension and pheochromocytoma. We conclude that the radioimmunoassay is at least equivalent to the colorimetric methods in distinguishing pathological and normal catecholamine secretion, and is faster, more precise, and 1000-fold more sensitive.

A sensitive and specific assay for free and sulfoconjugated normetanephrine, metanephrine, and 3-methoxytyramine was achieved by tetraphenylboron complexing and by high-performance liquid chromatography with electrochemical detection. Sulfoconjugated metabolites were hydrolyzed by sulfatase. Complexing the 3-O-methylated catecholamines with tetraphenylboron followed by their extraction in either and reextraction in dilute hydrochloric acid succeeded in partially purifying the sample without the use of a prepacked column. Detection by electrochemical technique additionally eliminates unoxidable components in the urine. The relatively high sensitivity of this method permits measurement of metabolite concentrations as low as 10 ng/ml, allowing for the first time the determination of free 3-O-methylated catecholamines in human urine. Hydrolysis by sulfatase specifically identifies the form of the conjugated metabolite. The mean total (free plus sulfoconjugated) values of normetanephrine, metanephrine, and 3-methoxytyramine obtained from 25 normal volunteers were 214, 102, and 227 micrograms/day, respectively. Values were greatly increased in patients with pheochromocytoma. The degree of sulfoconjugation varied, and each individual metabolite was highest with normetanephrine (86%). This method is sensitive, rapid, simple, and can be easily standardized for clinical investigation of pheochromocytoma.

We describe a sensitive procedure for measuring the basic catecholamine metabolites--normetanephrine, metanephrine, and 3-methoxytyramine--in urine by use of liquid chromatography, with electrochemical detection. These substances are isolated from hydrolyzed urine by passage through small ion-exchange columns and then pre-concentrated by a rapid set of solvent extractions before being injected onto the liquid-chromatographic column. Concentration and instrumental response are linearly related to 2.0 mg/liter for all three compounds, and practical lower detection limits are about 20 micrograms/liter for actual urine samples. The high selectivity that accrues from the combination of the extraction procedure, high-performance liquid chromatography, and electrochemical detection makes this procedure suitable for quantitative studies of catecholamine metabolism. A set of six samples can be taken through the extraction procedure in parallel in less than 2 h; once prepared, the extracts can be analyzed at a rate of three per hour.

A procedure has been developed for determining the O-methylated catecholamine metabolites, normetanephrine and metanephrine, in urine by use of radial-compression liquid chromatography followed by electrochemical detection. Normetanephrine and metanephrine are isolated from hydrolyzed urine by ion-exchange on small, commercially available, disposable columns and preconcentrated by solvent extraction. They are then separated by reversed-phase ion-pair chromatography, with use of a radial compression cartridge and radial compression module, and quantified with 3-methoxy-4-hydroxybenzylamine as internal standard. Normetanephrine, metanephrine, and the internal standard are separated from interfering peaks in about 15 min. The method is applicable to the relatively low amounts of normetanephrine (100-600 micrograms/24 h) and metanephrine (50-400 micrograms/24 h) found in normal subjects and patients with depressive disorders or hypertension. Within-day CVs ranged from 1.1 to 2.2% for normetanephrine and 1.2 to 6.9% for metanephrine; the corresponding between-day CVs were 4.9 and 5.7% over these ranges.

To facilitate the screening for pheochromocytoma, we have validated the use of single-voided, spot urine specimens for the determination of total metanephrines. Metanephrine excretion was found to be quite constant throughout the day and night in ten patients with essential hypertension and seven patients with pheochromocytoma. The levels in single-voided specimens were closely correlated to those in 24-hour specimens in 100 hypertensive subjects. The mean +/- 2 SD metanephrine excretion in single-voided urine specimens from 500 hypertensive subjects was 0.351 +/- 0.356 mug/mg of creatinine.

A method is described which extends a high performance liquid chromatographic assay for urinary catecholamines to the assay of urinary metanephrines. The amines are separated from urine after acid hydrolysis of conjugates by ion-exchange chromatography, and then further purified by solvent extraction. The final extracts are suitable for direct HPLC assay using the endogenous fluorescence of the amines for detection. Twenty-four hour excretion of the amines in 35 hospital in-patients was found to be (mean and range: 169 micrograms/24 h normetanephrine (39-423), 102 micrograms/24 h metanephrine (19-290) and 138 micrograms/24 h 3-methoxytyramine (32-234)).

A simple, direct and specific radioimmunoassay for serum and urinary metanephrine was developed, in which we used 125I-Synephrine and specific antiserum generated in rabbits by injecting with metanephrine conjugated with bovine serum albumin as described by Grota and Brown. The sensitivity of the assay was 2 pg/tube. Intra- and inter-assay coefficients of variation were 2.6 approximately 7.8% and 5.0 approximately 9.6%, respectively. The recoveries of metanephrine added at two levels of 250 pg/ml and 500 pg/ml to ten serum samples and ten urine samples (hydrolyzed and diluted) were 96.7 and 108% in serum, and 94.8 and 103% in urine, respectively. Normal values of serum metanephrine were 40.3 +/- 25.8 pg/ml (mean +/- SD) from 20 normal subjects. Normal values of 24 hour urinary metanephrine excretion were 12.5 +/- 6.7 ug/day from 24 normal subjects. Serum metanephrine values for 7 patients with pheochromocytoma were 210 approximately 628 pg/ml. Urinary metanephrine values for 9 patients with pheochromocytoma 8.7 approximately 302 ug/day.

We have previously reported high correlations between norepinephrine and its metabolite outputs in depressed patients. In this article, we expand this finding to healthy volunteers and alcoholic patients. Furthermore, we find similar high correlations between urinary outputs of dopamine, norepinephrine, and their major metabolites. The same is true, to a lesser degree, for epinephrine and metanephrine outputs. There are implications of these findings for psychobiological research on the monoamine systems.

Five patients with essential hypertension who were receiving treatment with the beta- and alpha-adrenoreceptor-blocking drug labetalol had elevated urinary excretion of catecholamines. When measured with a radioenzymatic assay, all five subjects had elevated urinary excretion of norepinephrine and normal urinary excretion of epinephrine; when measured with a fluorometric assay, four subjects had elevated urinary excretion of epinephrine with normal urinary excretion of norepinephrine, and one subject had elevated urinary norepinephrine excretion with normal urinary excretion of epinephrine. In three subjects who could be reevaluated three days to two months after labetalol therapy was discontinued, the urinary catecholamine levels had returned toward normal. Our studies indicate that labetalol produced a false elevation of urinary catecholamine levels. Although labetalol also interfered with the measurement of urinary excretion of metanephrine, it did not interfere with the measurement of urinary excretion of vanillylmandelic acid, homovanillic acid, 5-hydroxyindoleacetic acid, and serotonin, and it probably did not interfere with the measurement of plasma concentrations of dopamine, norepinephrine, and epinephrine. We conclude that labetalol therapy should be discontinued, and another beta-blocking drug, such as propranolol, that does not interfere with these tests should be temporarily substituted at least three days before a patient collects a 24-hour urine for measurement of the urinary excretion of catecholamines and metanephrine.

The urinary excretion of 3-methoxy-4-hydroxyphenylglycol (MHPG) and other catecholamine metabolites was measured in a series of 63 patients with various clinically defined subtypes of depressive disorders. MHPG excretion was significantly lower in patients with bipolar manic-depressive depressions and schizo-affective depressions than in patients with unipolar nonendogenous depressions. Patients with schizophrenia-related depressions also excreted reduced levels of MHPG when compared with patients with unipolar nonendogenous depressions. Moreover, levels of urinary epinephrine and metanephrine were significantly lower in patients with schizophrenia-related depressions. These data, coupled with our recent finding that patients with schizophrenia-related depressions had significantly higher levels of platelet monoamine oxidase activity than control subjects of patients with unipolar endogenous depressions, suggest that we can discriminate three biochemically discrete subgroups of depressive disorders corresponding to the following clinically defined subtypes: (1) the bipolar manic-depressive depressions plus the schizo-affective depressions; (2) the unipolar nonendogenous depressions; and (3) the schizophrenia-related depressions.

In this method for measuring metanephrine and normetanephrine in urine, they are freed from their conjugates by hydrolysis in acid, neutralized, and isolated on a cation-exchange resin. Both metanephrines are co-eluted with ammoniacal methanol and the eluate is concentrated 10-fold with respect to the original urine volume by evaporation and reconstitution. The recovered metanephrines ae separated by reversed-phase (C18) "high-pressure" liquid chromatography with use of a mobile phase consisting of 10 mmol/L trichloroacetate, pH 2.7, containing 30 mL of acetonitrile per liter. The metanephrines are detected at 365 nm after being converted to vanillin in a post-column reaction with alkaline periodate. 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.

We describe a simplified fluorometric method for quantitatively determining metanephrines in urine. The method is based on the elution of metanephrines from an ion-exchange column followed by production of a fluorescent derivative that has excitation and emission maxima of 405 nm and 505 nm, respectively. Metanephrine concentrations as great as 7.0 mg/L were within the linear range of the assay. Analytical recovery of metanephrines was 82-87%. Cross contamination by catecholamines was insignificant. The upper range of normal was 520 micrograms/24 h. Within-run and between-run CV's were 5% and about 9%, respectively. Twenty-four-hour urine specimens from five patients with pheochromocytoma showed above-normal amounts of the metanephrines by this method.

The previous article in this series reported on the differences in urinary excretion of 3-methoxy-4-hydroxyphenylglycol (MHPG) in patients with various clinically defined subtypes of depressive disorders. We now report that further biochemical discrimination among depressive subtypes is provided by the following equation, derived empirically by applying multivariate discriminant function analysis to data on urinary catecholamine metabolits: Depression-type (D-type) score = C1(MHPG) + C2(VMA) + C3(NE) +C4(NMN + MN)/VMA + C0. In the original derivation of this equation, low scores were related to bipolar manic-depressive depressions, and high scores were related to unipolar nonendogenous (chronic characterological) depressions. Findings from a series of depressed patients whose biochemical data had not been used to derive this equation confirmed these differences in D-type scores among subtypes of depressions. The findings presented in this report further suggest that we can discriminate three biochemically discrete subgroups of depressive disorders.