Determination of plasma 5-hydroxytryptophan, 5-hydorxytryptamine, 5-hydorxyindoleacetic acid, tryptophan and melatonin by high-performance liquid chromatography with electrochemical detection

Sagara, Yusuke; Okatani, Yuji; Yamanaka, S.; Kiriyama, Toshiaki

doi:10.1016/s0378-4347(00)83081-9

Cited by 69 publications

(25 citation statements)

References 12 publications

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“…Serum melatonin concentrations were determined by a method developed in our laboratory using high-performance liquid chromatography with electrochemical detection [15]. The assay had a sensitivity of 15 pg/ml, and intra-and interassay coefficients of variance were less than 10%.…”

Section: Assaymentioning

confidence: 99%

Enhanced Nocturnal Melatonin Secretion in Women with Functional Secondary Amenorrhea: Relationship to Opioid System and Endogenous Estrogen Levels

Okatani

Sagara

1995

Horm Res

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The purpose of this study was to evaluate the role of the opioid system and the estrogen environment in the nocturnal secretion of melatonin in women with secondary amenorrhea (SA). Nocturnal melatonin concentrations in patients with SA were significantly higher than in normal women (p < 0.01 vs. women with normal menstrual cycles). There were significant negative correlations between cumulative melatonin levels (between 8 p.m. and 8 a.m.) and serum estradiol-17β (r = -0.561, p < 0.01) and between peak serum melatonin values and serum estradiol-17β concentrations (r = -0.608, p < 0.01) in SA. Intravenous administration of a conjugated estrogen (Premarin 20 mg) significantly suppressed nocturnal melatonin secretion (p < 0.05), but a continuous intravenous infusion of naloxone (1.6 mg/h from 8 p.m. to 6 a.m.), an opiate antagonist, did not affect nocturnal melatonin secretion in SA. Our findings suggest that elevated nocturnal melatonin secretion may be related to low estrogen levels, but that it is not mediated by the opioid system.

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Section: Assaymentioning

confidence: 99%

Enhanced Nocturnal Melatonin Secretion in Women with Functional Secondary Amenorrhea: Relationship to Opioid System and Endogenous Estrogen Levels

Okatani

Sagara

1995

Horm Res

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“…5HTrp was separated on a 5-,um LC-18 column (25 x 0.46 cm with guard column; Supelco) using 100 mM sodium acetate/100 mM citrate, pH 4.1, containing 30 ,M EDTA and 4% (vol/vol) acetonitrile as mobile phase at 1.2 ml/min and detected fluorimetrically (302/345 nm, excitation/emission wavelengths) (29). Special care was taken in the analyses of tissue levels of 3HKyn and 3HAA, as these compounds easily autoxidize.…”

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confidence: 99%

Antioxidant activities of some tryptophan metabolites: possible implication for inflammatory diseases.

Christen

Peterhans

Stocker

1990

Proc. Natl. Acad. Sci. U.S.A.

295

179

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The antioxidant properties of tryptophan and some of its oxidative metabolites were examined by measuring how efficiently they inhibited peroxyl radical-mediated oxidation of phosphatidyicholine liposomes and B-phycoerythrin.Low micromolar concentrations of 5-hydroxytryptophan, 3-hydroxykynurenine, xanthurenic acid, or 3-hydroxyanthranilic acid, but not their corresponding nonhydroxylated metabolic precursors, scavenged peroxyl radicals with high efficiency. In particular, 3-hydroxykynurenine and 3-hydroxyanthranilic acid protected B-phycoerythrin from peroxyl radical-mediated oxidative damage more effectively than equimolar amounts of either ascorbate or Trolox (a water-soluble analog of vitamin E). Enzyme activities involved or related to oxidative tryptophan metabolism, as well as endogenous concentrations of tryptophan and its metabolites, were determined within tissues of mice suffering from acute viral pneumonia.

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“…Assay Scrum or plasma was separated within 1 hour of blood sample acquisition and stored at -8 0°C until melatonin, prolactin and 13-endorphin concentration assays were performed. Serum melatonin concentrations were determined using a method developed in our laboratory based on high-performance liquid chromatography with electrochemical detection [8], This assay has a sensitivity of 15 pg/ ml. and intra-and interassay coefficients of variance of less than 10%.…”

Section: Subjectsmentioning

confidence: 99%

Stimulation of Prolactin Secretion by Melatonin Is Not Mediated by Opioids

Okatani

Okada²,

Sagara³

1994

Horm Res

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To clarify the role the opioid system plays in mediating the stimulation of prolactin release by melatonin, we performed two separate studies between the 6th and 8th days of the follicular phase in normal young women. In the first study, serum prolactin concentrations were determined every 20 min over a 4-hour period following oral administration of melatonin (1 mg given at 13.00 h) in the presence of continuous intravenous infusion of saline or naloxone (1.6 mg/h), an opiate antagonist. In the second study, plasma β-endorphin concentrations were measured over a 3-hour period following oral melatonin administration (1 mg given at 13.00 h). Oral melatonin administration alone induced a significant increase in serum prolactin concentration, which was maximal 3 h after melatonin administration. Prolactin release following melatonin administration was not affected by continuous intravenous infusion of naloxone. No significant change in plasma β-endorphin concentrations was observed following melatonin administration. These findings strongly suggest that the stimulation of prolactin release by melatonin is not mediated by opioids.

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Determination of plasma 5-hydroxytryptophan, 5-hydorxytryptamine, 5-hydorxyindoleacetic acid, tryptophan and melatonin by high-performance liquid chromatography with electrochemical detection

Cited by 69 publications

References 12 publications

Enhanced Nocturnal Melatonin Secretion in Women with Functional Secondary Amenorrhea: Relationship to Opioid System and Endogenous Estrogen Levels

Enhanced Nocturnal Melatonin Secretion in Women with Functional Secondary Amenorrhea: Relationship to Opioid System and Endogenous Estrogen Levels

Antioxidant activities of some tryptophan metabolites: possible implication for inflammatory diseases.

Stimulation of Prolactin Secretion by Melatonin Is Not Mediated by Opioids

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