Study of diurnal fluctuations of plasma methoxyamines in healthy volunteers

Hoizey, Guillaume; Lukas-Croisier, C.; Frances, Carole; Grulet, H.; Delemer, Brigitte; Millart, Hervé; Devillier, Philippe; Caron, J.

doi:10.1046/j.0300-0664.2001.01446.x

Cited by 9 publications

(6 citation statements)

References 10 publications

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“…Total metanephrines are relatively easy to measure and rather stable (we found no loss of blood-conjugated metanephrines during repetitive measurement of a sample stored at 4 8C for several days) compared with the limited stability of plasma free metanephrines or whole blood catecholamines (26). Moreover, total metanephrines fluctuate minimally over the day, either in healthy volunteers or in pheochromocytoma patients (9,27), and are almost insensitive to stress compared with catecholamines (directly released from sympathetic nerves) or with free metanephrines (reactive to a lesser extent). Interestingly, pheochromocytoma cell cultures release free metanephrines (28), however without sulfoconjugating them, since concentrations of intracellular or secreted free metanephrines are equal to those of total metanephrines (data not shown).…”

Section: Discussionmentioning

confidence: 89%

Diagnostic accuracy of free and total metanephrines in plasma and fractionated metanephrines in urine of patients with pheochromocytoma

Grouzmann

Drouard-Troalen

Baudin

et al. 2010

European Journal of Endocrinology

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Background: Plasma free and urinary metanephrines are recognized biomarkers for the assessment of pheochromocytoma. Plasma total metanephrines with a long half-life may represent another useful biomarker. Objective: The aim of this study is to evaluate the diagnostic performances of plasma total metanephrines alone or combined with free metanephrines and fractionated 24-h urinary metanephrines. Methods: A retrospective, case-control diagnostic test study was conducted between 1999 and 2007 in two university hospitals in Switzerland and two institutions in France. The patients included 46 cases with histologically proven pheochromocytoma, and 181 controls suspected of tumor with negative investigations and 3-year follow-up. None had renal dysfunction. Sensitivity and specificity were compared after expressing each measurement result as a ratio over its upper reference limit, adding the ratios of normetanephrine and metanephrine, and defining cut-off values of 1 or 2 for this sum. Results: Applying a cut-off value of 1, plasma free and total metanephrines and urinary fractionated metanephrines had similar sensitivities of 96% (95% confidence interval, 86-99%), 95% (85-99%), and 95% (84-99%) along with similar specificities of 89% (83-94%), 91% (84-95%), and 86% (80-91%). A cut-off of 2 for the sum of ratios over reference limit improves the specificity, and it can be used for a confirmation test based on another biomarker taken among the three biomarkers. Conclusion: All three metanephrine-based tests perform equivalently for diagnosing pheochromocytoma in the absence of renal insufficiency, and can be conveniently associated two by two for confirming/excluding tumor.

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Section: Discussionmentioning

confidence: 89%

Diagnostic accuracy of free and total metanephrines in plasma and fractionated metanephrines in urine of patients with pheochromocytoma

Grouzmann

Drouard-Troalen

Baudin

et al. 2010

European Journal of Endocrinology

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“…If the tissue is noninnervated, then the NE concentration depends on plasma concentrations. Basal plasma NE is ϳ2-3 nmol/l and can increase 10-fold during exercise (25,30). Injury and inflammation can increase local NE release by locally activating nerves (13).…”

Section: Discussionmentioning

confidence: 99%

Norepinephrine-induced calcium signaling and expression of adrenoceptors in avian tendon cells

Wall

Faber

Yang³

et al. 2004

American Journal of Physiology-Cell Physiology

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Sympathetic efferent nerves are present in tendons, but their function within tendon is unknown. alpha(1)-Adrenoceptors are expressed by a variety of cell types. In the presence of norepinephrine (NE), adrenoceptors activate G(q/11) signaling pathways that subsequently increase intracellular Ca(2+) concentration ([Ca(2+)](ic)). It was hypothesized that avian tendon cells express functional adrenoceptors that respond to NE by increasing [Ca(2+)](ic). Avian tendon cells were analyzed for mRNA expression of alpha(1)-adrenoceptors by RT-PCR. Avian tendons expressed the alpha(1A)- and alpha(1B)-adrenoceptor subtypes. Furthermore, both tendon surface epitenon cells and internal fibroblasts infused with a Ca(2+)-sensitive dye, fura 2, and stimulated with NE responded by increasing [Ca(2+)](ic). KMD-3213, an alpha(1A)-adrenoceptor antagonist, significantly reduced the Ca(2+) response. Other adrenoceptor antagonists had no effect on the Ca(2+) response. The absence of extracellular Ca(2+) also significantly reduced the response to NE, indicating that Ca(2+) influx contributed to the rise in [Ca(2+)](ic). This study provides the first evidence that tendon cells express adrenoceptors and that the NE-induced Ca(2+) response is coupled to the alpha(1A)-adrenoceptor subtype.

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“…Upon completion of a phone screening interview, eligible participants were scheduled for an appointment between days 10 and 24 of the menstrual cycle to ensure that participants were not menstruating during the sexual psychophysiological assessment. As DA levels show a circadian rhythm, peaking at 10:00 and gradually declining over the day [68], and as NE levels do not demonstrate diurnal fluctuations [69], visits were scheduled between 10:00 am and 12:00 pm to control for DA fluctuations. Collection of urine during this time enabled participants to provide second‐morning urine samples, which, for our purposes, were superior to first‐morning samples, as first‐morning urine is often sour and concentrated, more suitable to the detection of bacteria and less appropriate for an accurate measure of catecholamines [70].…”

Section: Methodsmentioning

confidence: 99%

Emotional States of Love Moderate the Association Between Catecholamines and Female Sexual Responses in the Laboratory

Dundon

Rellini

2012

The Journal of Sexual Medicine

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Introduction Research suggests that there are three interrelated, yet distinct, emotion motivation brain systems for human love (lust, romantic love, and attachment), each associated with a unique catecholaminergic and hormonal profile. Of interest for the current study are norepinephrine (NE) and dopamine (DA), which have a hypothesized connection with romantic love. As NE and DA are also known to facilitate sexual arousal, it is plausible that NE and DA may have a greater positive association with the sexual arousal responses of women in romantic love compared with women in lust. Aim This study investigated if the effects of NE and DA activity on sexual arousal responses would differ depending on emotion motivation state (Lust or Romantic). Main Outcome Measures Physiological sexual arousal was assessed by photoplethysmography and subjective sexual arousal was assessed with a participant controlled lever. Methods Seventeen women were included in the Lust group and 29 in the Romantic group. All participants provided a urine sample (to assess NE and DA) and completed a psychophysiological assessment. Results Elevated NE was positively and significantly associated with greater subjective and physiological sexual arousal for the Lust group, but not for the Romantic group. Similarly, elevated DA was positively and significantly associated with greater subjective sexual arousal for the Lust group, but not for the Romantic group. Conclusions The sexual arousal responses of women in the Lust group, but not in the Romantic group, were positively and significantly associated with elevated NE and DA. It is feasible that, when women are seeking a partner (Lust), NE and DA may facilitate attention toward sexually relevant stimuli.

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Study of diurnal fluctuations of plasma methoxyamines in healthy volunteers

Cited by 9 publications

References 10 publications

Diagnostic accuracy of free and total metanephrines in plasma and fractionated metanephrines in urine of patients with pheochromocytoma

Diagnostic accuracy of free and total metanephrines in plasma and fractionated metanephrines in urine of patients with pheochromocytoma

Norepinephrine-induced calcium signaling and expression of adrenoceptors in avian tendon cells

Emotional States of Love Moderate the Association Between Catecholamines and Female Sexual Responses in the Laboratory

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