Unprecedented high catecholamine production causing hair pigmentation after urinary excretion in red deer.

Hormones have not been found in concentrations of orders of magnitude higher than nanograms per milliliter. Here, we report urine concentrations of a catecholamine (norepinephrine) ranging from 0.05 to 0.5 g/l, and concentrations of its metabolite DL-3,4-dihydroxyphenyl glycol (DOPEG) ranging from 1.0 to 44.5 g/l, in wild male red deer Cervus elaphus hispanicus after LC-MS analyses. The dark ventral patch of male red deer, a recently described sexually selected signal, contains high amounts of DOPEG (0.9-266.9 mg/l) stuck in the hairs, while DOPEG is not present in non-darkened hair. The formation of this dark patch is explained by the chemical structure of DOPEG, which is a catecholamine-derived o-diphenol susceptible to be oxidized by air and form allomelanins, nitrogen-free pigments similar to cutaneous melanins; by its high concentration in urine; and by the urine spraying behavior of red deer by which urine is spread through the ventral body area. Accordingly, the size of the dark ventral patch was positively correlated with the concentration of DOPEG in urine, which was in turn correlated with DOPEG absorbed in ventral hair. These findings represent catecholamine concentrations about one million higher than those previously reported for any hormone in an organism. This may have favored the evolution of the dark ventral patch of red deer by transferring information on the fighting capacity to rivals and mates. Physiological limits for hormone production in animals are thus considerably higher than previously thought. These results also unveil a novel mechanism of pigmentation based on the self-application of urine over the fur.

Belief in life after death, salivary 3-methoxy-4-hydroxyphenylglycol, and well-being among older people without cognitive impairment dwelling in rural Japan.

OBJECTIVES: Research has found that spirituality/religiosity has a salutary association with mental/physical health. However, the association of belief in life after death with well-being has rarely been studied, and the same is true of its association with biological indices, such as monoamine transmitters. Therefore, we examined the associations between well-being and religiosity, salivary 3-methoxy-4-hydroxyphenylglycol (sMHPG), and demographic characteristics. METHODS: The participants were 346 community-dwelling people, aged 65 years or older, without cognitive or mental deficits, in rural Japan. Measures of religiosity consisted of belief in life after death, attachment to life, and experiences related to death and religion. The measures were assessed by scales specifically suited for Japanese religious orientations. Participants' well-being was assessed by a life satisfaction scale containing two subscales. We also measured sMHPG, a major metabolite of noradrenaline that is thought to reflect certain psychological states, such as psychomotor retardation and effortful attention. RESULTS: One subscale of life satisfaction was positively associated with belief in life after death and sMHPG, and the other life satisfaction subscale was positively associated with education and death/religion-related experiences (e.g., visiting family graves or loss of a friend). Gender differences were found in afterlife beliefs and each life satisfaction subscale. CONCLUSIONS: These results suggest that religiosity, including belief in life after death and death/religion-related experiences, is salubriously associated with mental health among older people, especially women, living in rural Japan. The basal level of sMHPG was positively associated with life satisfaction, but not with belief in life after death.

Effects of duloxetine on norepinephrine and serotonin transporter activity in healthy subjects.

Duloxetine selectively inhibits the serotonin (5-HT) and norepinephrine (NE) transporters (5-HTT and NET, respectively), as demonstrated in vitro and in preclinical studies; however, transporter inhibition has not been fully assessed in vivo at the approved dose of 60 mg/d. Here, the in vivo effects of dosing with duloxetine 60 mg once daily for 11 days in healthy subjects were assessed in 2 studies: (1) centrally (n = 11), by measuring concentrations of 5-hydroxyindoleacetic acid, 3,4-dihydroxyphenylglycol (DHPG), and NE in cerebrospinal fluid, and (2) versus escitalopram 20 mg/d (n = 32) in a 2-period crossover study by assessing the ΔDHPG/ΔNE ratio in plasma during orthostatic testing and by pharmacokinetic/pharmacodynamic modeling of reuptake inhibition using subjects' serum in cell lines expressing cloned human 5-HTT or NET. At steady state, duloxetine significantly reduced concentrations of DHPG and 5-hydroxyindoleacetic acid (P < 0.05), but not NE, in cerebrospinal fluid; DHPG was also decreased in plasma and urine. The ΔDHPG/ΔNE ratio in plasma decreased significantly more with duloxetine than escitalopram (65% and 21%, respectively; P < 0.0001). Ex vivo reuptake inhibition of 5-HTT was comparable (EC50 = 44.5 nM) for duloxetine and escitalopram, but duloxetine inhibited NET more potently (EC50 = 116 nM and 1044 nM, respectively). Maximal predicted reuptake inhibition for 5-HTT was 84% for duloxetine and 80% for escitalopram, and that for NET was 67% and 14%, respectively. In summary, duloxetine significantly affected 5-HT and NE turnover in the central nervous system and periphery; these effects presumably occurred via inhibition of reuptake by the 5-HTT and NET, as indicated by effects on functional reuptake inhibition ex vivo.

MHPG excretion in depressive disorders: relation to clinical subtypes and desynchronized sleep.

The urinary excretion of 3-methoxy-4-hydroxyphenylglycol (MHPG) was significantly lower in patients with manic-depressive depressions than in patients with chronic characterological depressions. There was an inverse relationship between MHPG excretion and the amount of time spent in desynchronized sleep, particularly in the manic-depressive disorders. Excretion of MHPG was not related to the degree of retardation, agitation, or anxiety in these patients.

3-Methoxy-4-hydroxyphenethyleneglycol production by human brain in vivo.

A direct method has been employed to estimate the rate of production by human brain of 3-methoxy-4-hydroxyphenethyleneglycol, the major metabolite of brain norepinephrine, a brain neurotransmitter. Venous specimens were obtained from the internal jugular vein from ten awake human subjects at a puncture site above the common facial vein, the first major source of extracranial inflow. Arterial specimens were simultaneously obtained from the radial artery. Plasma samples were assayed and a highly significant difference was found in the concentration of the metabolite in plasma coming out of the brain (venous blood) as compared to plasma entering the brain (arterial blood). This venous-arterial difference was calculated to be 0.7 +/- 0.1 nanogram per milliliter of blood. Assuming an adult brain weight of 1400 grams and normal cerebral blood flow, it is estimated that the rate of production of 3-methoxy-4-hydroxyphenethyleneglycol by the awake human brain is approximately 597 nanograms per minute or 35.8 micrograms per hour. Urine specimens were also collected from six of these subjects during a period of 1 to 3.5 hours, which bracketed the time the blood samples were obtained. For these six subjects the output of 3-methyoxy-4-hydroxyphenethyleneglycol by whole brain was estimated to be 40.9 micrograms per hour, whereas the rate of its excretion into urine was 64.5 micrograms per hour.

A phase 1 trial of pharmacologic interactions between transdermal selegiline and a 4-hour cocaine infusion.

BACKGROUND: The selective MAO-B inhibitor selegiline has been evaluated in clinical trials as a potential medication for the treatment of cocaine dependence. This study evaluated the safety of and pharmacologic interactions between 7 days of transdermal selegiline dosed with patches (Selegiline Transdermal System, STS) that deliver 6 mg/24 hours and 2.5 mg/kg of cocaine administered over 4 hours. METHODS: Twelve nondependent cocaine-experienced subjects received deuterium-labeled cocaine-d5 intravenously (IV) 0.5 mg/kg over 10 minutes followed by 2 mg/kg over 4 hours before and after one week of transdermal selegiline 6 mg/24 hours. Plasma and urine were collected for analysis of selegiline, cocaine, catecholamine and metabolite concentrations. Pharmacodynamic measures were obtained. RESULTS: Selegiline did not change cocaine pharmacokinetic parameters. Selegiline administration increased phenylethylamine (PEA) urinary excretion and decreased urinary MHPG-sulfate concentration after cocaine when compared to cocaine alone. No serious adverse effects occurred with the combination of selegiline and cocaine, and cocaine-induced physiological effects were unchanged after selegiline. Only 1 peak subjective cocaine effects rating changed, and only a few subjective ratings decreased across time after selegiline. CONCLUSION: No pharmacological interaction occurred between selegiline and a substantial dose of intravenous cocaine, suggesting the combination will be safe in pharmacotherapy trials. Selegiline produced few changes in subjective response to the cocaine challenge perhaps because of some psychoactive neurotransmitters changing in opposite directions.

Physiological approaches to assess diminished sympathetic activity in the conscious rat.

The purpose of this study was to evaluate functional measures of diminished sympathetic activity after postganglionic neuronal loss in the conscious rat. To produce variable degrees of sympathetic postganglionic neuronal loss, adult rats were treated daily with toxic doses of guanethidine (100mg/kg) for either 5days or 11days, followed by a recovery period of at least 18days. Heart rate, blood pressure, cardiac baroreflex responsiveness, urinalysis (for catecholamine metabolite, 3-methoxy-4-hydroxyphenylethylenglycol; MHPG), and pupillometry were performed during the recovery period. At the end of the recovery period stereology of superior cervical ganglia (SCG) was performed to determine the degree of neuronal loss. Total number of SCG neurons was correlated to physiological outcomes using regression analysis. Whereas guanethidine treatment for 11days caused significant reduction in the number of neurons (15,646±1460 vs. 31,958±1588), guanethidine treatment for 5days caused variable levels of neuronal depletion (26,009±3518). Regression analysis showed that only changes in urinary MHPG levels and systolic blood pressure significantly correlated with reduction of SCG neurons (r2=0.45 and 0.19, both p<0.05). Although cardiac baroreflex-induced reflex tachycardia (345.7±19.6 vs. 449.7±20.3) and pupil/iris ratio (0.50±0.03% vs. 0.61±0.02%) were significantly attenuated in the 11-day guanethidine treated rats there was no significant relationship between these measurements and the number of remaining SCG neurons after treatment (p>0.05). These data suggest that basal systolic blood pressure and urinary MHPG levels predict drug-induced depletion of sympathetic activity in vivo.

Clinical assessment of norepinephrine transporter blockade through biochemical and pharmacological profiles.

BACKGROUND: To assess the sensitivity of biochemical, physiological, and pharmacological markers of peripheral norepinephrine (NE) transporter (NET) function, we chronically antagonized NET by a range of doses of duloxetine [(+)-N-methyl-3-(1-naphthalenyloxy)-2 thiophenepropanamine], which blocks the NE reuptake process. METHODS AND RESULTS: Duloxetine was administered in a randomized, placebo-controlled study in 15 healthy volunteers. Plasma from duloxetine-treated subjects (ex vivo effect) dose-dependently decreased radioligand binding to human NET (maximum inhibition was 60%) (P=0.02). The dose of intravenous tyramine required to raise systolic blood pressure by 30 mm Hg (PD30) increased dose-dependently with duloxetine and was significant at the end of the 120-mg/d dosage (P<0.001). The plasma dihydoxyphenylglycol to NE (DHPG/NE) ratio was reduced significantly at 2 weeks of treatment with 80 mg/d duloxetine (11.3 at baseline, 3.4 at 240 mg/d, P<0.001). Plasma NE was significantly increased starting at 120 mg/d duloxetine. Urine results (corrected for 24-hour creatinine excretion) showed a dose-dependent change from the baseline urinary excretion for NE, DHPG, and the DHPG/NE ratio. The most sensitive measure, the DHPG/NE ratio, was significant at the 80-mg dose. Urinary NE excretion was significantly raised after 2 weeks of treatment with 80 mg/d duloxetine (P<0.001), the lowest dose used in the study. CONCLUSIONS: These findings suggest that the degree of NET blockade can be assessed with the plasma or urine DHPG/NE ratio and the pressor effect of tyramine. Also, the DHPG/NE ratio is more sensitive at the lower end of NET inhibition, whereas tyramine exhibits a linear relation, with NET inhibition commencing at a higher dose.

Primary affective disorder, clinical state change, and MHPG excretion: a longitudinal study.

Urinary 3-methoxy-4-hydroxyphenethylene glycol (MHPG) excretion, which is thought to reflect CNS norepinephrine metabolism, has been shown to be significantly decreased in some depressed patients. Although there is consensus that urinary MHPG excretion varies directly with mood in rapidly cycling bipolar patients, there is little information on longer term state changes, such as those that accompany recovery from depression. Ten female patients with diagnoses of primary affective disorder were studied initially during an inpatient hospitalization and restudied at least ten months after discharge. Five healthy female comparison subjects were also studied over a similar interval of time. During the baseline period, the patient sample excreted less MHPG than did the comparison group. Improvement in clinical state from a seriously depressed baseline was associated with a significant increase in MHPG excretion, while the patients with recurrences of depression showed no change and continued to excrete less MHPG than the comparison subjects. These results suggest that urinary MHPG excretion may represent an index of psychobiological state in depressive patients.

State anxiety, physical activity, and urinary 3-methoxy-4-hydroxyphenethylene glycol excretion.

Measurement of urinary 3-methoxy-4-hydroxyphenethylene glycol (MHPG) levels has been suggested as possibly being important in elucidating the role of central noradrenergic function in affective illnesses. The influence on urinary MHPG excretion of the state variables of physical activity and stress has not been clearly defined in previous studies. During a baseline medication-free period, 24 hospitalized depressed female patients underwent a five-day protocol including an eight-hour period of either enhanced or restricted activity. Throughout the protocol, independent measurements of telemetered mobility and stale anxiety were obtained. There were no significant effects of physical activity on urinary MHPG levels. Furthermore, baseline urinary MHPG levels and baseline state anxiety did not covary significantly. However, within-individual analyses yielded a highly significant relationship between changes in urinary MHPG levels and changes in state anxiety. The data suggested that those patients with lower baseline MHPG levels were those more prone to experience increased anxiety under environmentally "activating" circumstances.

Excretion of MHPG in normal subjects: implications for biological classification of affective disorders.

Exretion of 3-methoxy-4-hydroxyphenylglycol (MHPG) was measured repeatedly in 17 normal subjects. The amount of MHPG excreted over a 24-hour period was fairly stable over a period of three consecutive 24-hour samplings, but stability was rather poor over subsequent periods of several weeks, suggesting that execretory patterns are not traits. A normal range of MHPG excretion was estimated to be 900 to 3,500 micrograms/24 hr. This range covers the majority of persons with affective disorders whose excretion patterns have been measured, although comparisons of absolute values between laboratories must be made cautiously. Further, substantial changes within this range may occur in normal subjects with no accompanying change in affect. A slight but definite diurnal pattern of excretion was found, with a peak at the period of 1600 to 1800 hours. No clear relationship to MHPG excretion to state of physical activity, recent consumption of foods or beverages, or prevailing affective state was defined in those subjects living under normal conditions. While MHPG excretion may yet prove useful for categorizing depressed patients and predicting response to drugs, any inferences drawn regarding the pathogenesis of affective disorders must be guarded.

Plasma free and conjugated MHPG in psychiatric patients. A pilot study.

Measures of plasma 3-methoxy-4-hydroxyphenethyleneglycol (MHPG) may be useful for investigating noradrenergic function in certain behavioral and physiologic states. Serial plasma and urine samples were obtained from a diagnostically heterogeneous group of ten psychiatric inpatients over a three- to five-day period. The plasma samples were assayed for free and total MHPG and the urine samples for total MPHG. The variance between patients in both plasma free and conjugated MHPG was markedly greater than the variance within patients. The test-retest reliability for free plasma MHPG in both AM vs PM values within and across study days was also significant for both free and conjugated MHPG even though the AM plasma free MHPG values were significantly greater than the PM values. No significant correlations were found between plasma free and conjugated MHPG or between urinary total MHPG and plasma free MHPG.

Urinary MHPG levels and tricyclic antidepressant drug selection. A preliminary communication on improved drug selection in clinical practice.

The 24-hour urinary 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) output was used as the basis for selection of tricyclic antidepressant drug therapy for the depressed patient population treated by one psychiatrist over a period of ten months in a psychiatric clinic. Use of MHPG output level as the criterion for drug selection resulted in significantly better clinical results than had been obtained previously by the same psychiatrist using more traditional selection methods on a similar depressed patient population. A correlation was noted between patients' pretreatment MHPG output levels and three symptoms of depression (guilt, agitation, and diurnal variation) as measured on the Hamilton Rating Scale for Depression.

Urinary 3-methoxy-4-hydroxyphenylglycol circadian rhythm. Early timing (phase-advance) in manic-depressives compared with normal subjects.

Twenty-four-hour (circadian) rhythms in urinary 3-methoxy-4-hydroxyphenylglycol (MHPG) excretion, motor activity, and oral temperature were studied in 14 normal subjects and ten manic-depressive patients. In both groups, a daily rhythm in MHPG excretion was present, with daytime peaks and nighttime lows. This pattern of urinary MHPG excretion may reflect a rhythm in central noradrenergic function. The physiological changes in levels of MHPG excretion associated with the circadian rhythm were at least as great as pathological changes associated with manic-depressive illness. Compared with controls, the timing or phase of circadian rhythms in each variable was one to three hours earlier in the patients, whether depressed or manic. Although the presence of circadian rhythms complicates the task of designing clinical research procedures, their early timing in manic-depressives suggests that disturbances in central biological clocks may be an integral part of the pathophysiology of affective illness and may be related to disturbances of sleep and neuroendocrine function associated with depression.

Subtypes of depression based on excretion of MHPG and response to nortriptyline.

We investigated the relationship between urinary excretion of MHPG and the clinical response of 17 depressed patients to nortriptyline hydrochloride. Plasma concentrations of nortriptyline were monitored to assure optimal doses. Patients were classified as having "low" or "normal-high" excretion of MHPG based on one to five 24-hour urine specimens. Hamilton Depression Rating Scale scores were not reduced significantly more among the nine low excreters as compared with the eight normal-high excreters. However, when a true bimodal distribution of MHPG excretion was created by comparing only the six lowest excreters with the six highest excreters, the low group improved significantly more than the high group. This differential response to nortriptyline somewhat supports the notion that MHPG excretion may predict response to specific tricyclics. Collecting urine for MHPG determination in depressed patients is not easy; the variability of excretion within patients is considerable, and the range of MHPG excretion closely parallels that in normal persons. The clinical utility of this procedure is still to be determined.

Antidepressant response to tricyclics and urinary MHPG in unipolar patients. Clinical response to imipramine or amitriptyline.

The urinary excretion of the norepinephrine metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) was measured in unipolar depressed patients before and during the fourth week of treatment with either imipramine hydrocloride or amitriptyline hydroxhloride. On the basis of strict rating criteria, 24 patients were selected as either unequivocal responders or nonresponders. In the imipramine group the mean pretreatment MHPG was significantly lower in the nine responders in the seven nonresponders; the converse was found with the amitriptyline patients. Of particular interest is that there was no overlap in individual values between the responders and nonresponders to either drug. Treatment with eigher imipramine or amitriptyline was associated with a significant decrease in MHPG excretion, which was independent of clinical response.

High correlation of norepinephrine and its major metabolite excretion rates.

Twenty-four-hour urinary excretion rates of norepinephrine, normetanephrine, 3-methoxy-4-hydroxyphenylglycol, and (vanillylmandelic) acid were repeatedly measured in 12 depressed patients. High (greater than. 83) positive correlations were found between the excretion rates of these four substances. Based on these findings, the conclusion was reached that in depressed patients the 24-hour urinary excretion rates of norepinephrine and any of its three major metabolites reflect total norepinephrine production in the body.

Extraversion in pathological gamblers. Correlates with indexes of noradrenergic function.

Pathological gamblers may have a disturbance of their central nervous system noradrenergic functioning. We administered the Eysenck Personality Questionnaire to pathological gamblers and examined relationships between their personality scores on this questionnaire and indexes of noradrenergic function. There were highly significant correlations between scores on the extraversion scale and cerebrospinal fluid levels of 3-methoxy-4-hydroxyphenylglycol, plasma levels of 3-methoxy-4-hydroxyphenylglycol, urinary outputs of vanillylmandelic acid, as well as with the sum of urinary outputs of norepinephrine and its major metabolites. These results suggest that the disturbance in the central noradrenergic system in pathological gamblers may be partly reflected in their personality.

Conversion of MHPG to vanillylmandelic acid. Implications for the importance of urinary MHPG.

Deuterium-labelled 4-hydroxy-3-methoxyphenylglycol (MHPG), when administered intravenously, is rapidly converted to 4-hydroxy-3-methoxymandelic acid (or vanillylmandelic acid [VMA]) or conjugates of MHPG. Since over half of either racemic D,L-MHPG or the natural D-MHPG is converted to VMA and since about half of urinary VMA is derived from MHPG, estimates of the proportion of urinary MHPG derived from the brain must be revised. The results indicate that only about one fifth of urinary MHPG is derived from the brain, and clearly urinary MHPG cannot be used as a valid index of brain norepinephrine metabolism. While these observations do not alter the value of urinary MHPG as a predictor of therapeutic response or in subclassifying affective disorders, it is clear that new research questions must be formulated and appropriate investigations completed before the relationship of urinary MHPG to affective disorders is understood.

Toward a biochemical classification of depressive disorders. I. Differences in urinary excretion of MHPG and other catecholamine metabolites in clinically defined subtypes of depressions.

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.