Serum Melatonin Concentrations Research Articles

Dual effects of melatonin on uterine myoelectrical activity of non-pregnant rats

In this experimental study, we aimed to investigate the role of melatonin on uterine myoelectrical activity of non-pregnant rats. Forty-six female rats were assigned to six groups: (1) control; (0.2 mL 0.9% NaCl was injected intravenously (IV), n=6); (2) melatonin applied as 0.4 mg/kg/IV (n=8); (3) melatonin applied as 4 mg/kg/IV (n=8); (4) single dose of oxytocin (100 mU/kg) injected IV (n=8); (5) melatonin (0.4 mg/kg) plus oxytocin (100 mU/kg) (n=8); and (6) melatonin (4 mg/kg) plus oxytocin (100 mU/kg) injected IV (n=8). Each rat underwent a laparotomy, and uterine myoelectrical signals were recorded. The mean spectrum, averaged over the spectral content of signals in each group, was compared. Melatonin induced uterine myoelectrical activity in a dose-dependent manner. Treatment of melatonin after oxytocin suppressed the mean power of the signals. Serum melatonin concentrations were significantly higher in melatonin-treated rats. Melatonin itself at two different dose levels was found to be equally effective in stimulating the uterine electrical signals, although oxytocin-induced uterine electrical activity was suppressed by melatonin. These findings merit further investigations on the possible beneficial role of melatonin in the treatment of conditions associated with abnormal uterine activity.

Melatonin in perimenopausal and postmenopausal women

Melatonin synthesis and secretion are partly modulated by estrogen and progesterone. Changes in melatonin concentrations, possibly related to the menopausal transition, may be associated with climacteric mood, sleep, and vasomotor symptoms. The aims of this study were to compare the serum concentrations of melatonin in perimenopausal and postmenopausal women and to evaluate melatonin's influence on mood, sleep, vasomotor symptoms, and quality of life. We analyzed the data of 17 healthy perimenopausal women (aged 43-51 y) and 18 healthy postmenopausal women (aged 58-71 y) who participated in a prospective study. On study night (9:00 pm-9:00 am), serum melatonin was sampled at 20-minute (9:00 pm-12:00 midnight; 6:00-9:00 am) and 1-hour (12:00 midnight-6:00 am) intervals. Questionnaires were used to assess depression (Beck Depression Inventory), anxiety (State-Trait Anxiety Inventory), insomnia and sleepiness (Basic Nordic Sleep Questionnaire [BNSQ]), subjective sleep quality, vasomotor symptoms, and quality of life (EuroQoL). Postmenopausal women had lower nighttime serum melatonin concentrations than perimenopausal women. The duration of melatonin secretion tended to be shorter in postmenopause, whereas melatonin peak time did not differ. Mean melatonin concentrations and exposure levels did not correlate with follicle-stimulating hormone level, estradiol level, body mass index, Beck Depression Inventory score, State-Trait Anxiety Inventory score, BNSQ insomnia score, BNSQ sleepiness score, subjective sleep score, climacteric vasomotor score, or quality of life. In perimenopause, the later is the melatonin peak, the higher is the level of anxiety (P = 0.022), and the longer is the melatonin secretion, the better is the quality of life (P < 0.001). Longitudinal research is needed to better understand the possible contributory role of menopause in lower melatonin levels.

Effect of prepartum photoperiod and melatonin feeding on milk production and prolactin concentration in dairy heifers and cows

Holstein multiparous cows (n=29) and primiparous heifers (n=32) calving over a 1-yr period were subjected to photoperiod-melatonin treatments according to a 2×3 factorial design. Starting 8wk before expected calving, all animals were subjected to 1 of the following treatments: 8h of light and 16h of dark (8L:16D), 16h of light and 8h of dark (16L:8D), or 16L:8D plus melatonin feeding (16L:8D-melatonin). Each day at 1355h, the animals in the melatonin treatment received orally a gelatin capsule containing 25mg of melatonin. The treatments ended at calving, when the animals were moved to the lactation barn; all animals were then subjected to about 16h of light per day. At the beginning and end of the treatment period before calving, blood samples were taken from 6heifers and 6cows through a jugular cannula for 24h at 30-min intervals to monitor serum melatonin and prolactin concentrations. Milk production in the heifers was not affected by the photoperiod treatments. Early-lactation milk production was higher in the cows exposed to the short-day photoperiod than in those exposed to a long-day photoperiod (16L:8D and 16L:8D-melatonin), with averages of 36.7±0.9, 33.1±0.8, and 34.1±0.9kg/d for 8L:16D, 16L:8D, and 16L:8D-melatonin, respectively. Photoperiod had no effect on late-lactation milk production in the cows. During lactation, the dry matter intake of heifers was not affected by the treatments, but dry matter intake of the cows exposed to a short-day photoperiod was greater than that of the cows exposed to a long-day photoperiod. Feed efficiency of heifers was improved by short-day photoperiod. During the treatment period, prolactin concentration was lower in the animals exposed to a short-day photoperiod than in those exposed to a long-day photoperiod, was lower with the 16L:8D-melatonin treatment than with the 16L:8D treatment, and tended to be lower with the 8L:16D treatment than with the 16L:8D-melatonin treatment, with averages of 3.5±0.8, 9.9±0.8, and 6.0±0.8ng/mL for 8L:16D, 16L:8D, and 16L:8D-melatonin, respectively. In early lactation, prolactin concentration was lower in the heifers exposed to the 16L:8D photoperiod during the dry period than in those exposed to the 8L:16D photoperiod or fed melatonin. In conclusion, a short-day photoperiod during the dry period transiently increases milk production of cows and the feed efficiency of heifers in the following lactation. However, melatonin cannot be used to mimic a short-day photoperiod during the dry period.

Effects of photoperiod on broodiness, egg-laying and endocrine responses in native laying hens

1. The effects of photoperiod on broodiness, egg-laying and endocrine responses in native laying hens were investigated. A total of 648, 18-week-old native laying hens (Beijing You Chicken, BYC) were randomly allocated to 6 groups with 3 replicates. The birds were exposed to 1 of 6 different photoperiods, including 16L:8D (06:00 to 22:00 h) for group 1; 12L:2D:4L:6D for group 2; 8L:4D:4L:8D for group 3; 16L:8D (03:00 to 19:00 h) for group 4; 14L:10D for group 5; and 18L:6D for group 6.2. The broodiness rate and egg-laying rate for weeks 20–26, 27–33, 34–40, 41–47, 48–54 and 55–61 were calculated, and serum prolactin (PRL), luteinising hormone (LH), 17-beta-oestradiol (E2), melatonin (Mel) and progesterone (P4) concentrations were measured at the end of each stage.3. Significant effects were observed on the rate of broodiness by the photoperiod and stage, but the interaction of photoperiod and stage was not significant. The rate of broodiness for group 3 (5.9%) was significantly higher than other groups, with group 2 being the lowest (2.8%). Broodiness rate was the highest for weeks 41–47 (9.9%). Significant effects were observed on average egg-laying rate by photoperiod and stage: the rate of egg-laying of groups 2 and 5 were significantly higher than groups 1, 4 and 6.4. There were no significant effects of photoperiod on PRL, LH and Mel concentrations at 26, 33, 40 and 54 weeks of age (P > 0.05), but at 47 weeks of age, PRL and LH concentrations of group 1 were significantly lower than those in other groups.5. The study suggests that the photoperiod of group 2 (12L:2D:4L:6D) is optimal for the birds’ performance to give the lowest broodiness rate and the highest egg-laying rate during the whole laying period, and 41–47 weeks may be a key stage for the photomodulation of broodiness.

Elevated melatonin levels in natalizumab-treated female patients with relapsing-remitting multiple sclerosis: Relationship to oxidative stress

Natalizumab is currently the most successful clinical treatment for multiple sclerosis. The use of this drug is associated with the reduction in the number of relapses and a slowing in disease progression, as well as an improvement in signs and symptoms displayed by the patients. To evaluate the effect of natalizumab on melatonin and its relationship with peripheral oxidative damage, we studied the serum melatonin levels in 18 patients with relapsing-remitting multiple sclerosis. Natalizumab caused significant increases in serum melatonin concentrations. This change was associated with a rise in increase of antioxidants and a reduction in oxidative stress biomarkers. In conclusion, these data may explain, at least in part, some of the beneficial effects exhibited by disease antibody such as its antioxidant capacity.

The effect of hormone therapy on serum melatonin concentrations in premenopausal and postmenopausal women: A randomized, double-blind, placebo-controlled study

ObjectivesMelatonin levels decrease physiologically with age, and possibly with the transition to menopause. The plausible influence of hormone therapy (HT) on melatonin is poorly understood. The aim of this randomized, placebo-controlled, double-blind trial was to investigate the effect of HT administration on serum melatonin concentrations in late premenopausal and postmenopausal women. Study designAnalyses were carried out among 17 late premenopausal and 18 postmenopausal healthy women who participated in a prospective HT study in Finland. Serum melatonin was sampled at 20-min (21:00–24:00h; 06:00–09:00h) and 1-h (24:00–06:00h) intervals at baseline and after 6 months with HT or placebo. Main outcome measuresMelatonin levels and secretion profile after 6 months of HT compared to placebo. ResultsMean melatonin levels, mean melatonin exposure level (area under curve, AUC) and mean duration of melatonin secretion did not differ after 6 months with HT vs. placebo, irrespectively of the reproductive state. However, in postmenopausal women the melatonin peak time (acrophase) was delayed by 2.4h (2h 21min) on average after 6 months with HT vs. placebo (p<0.05). No interaction between time and group was detected when melatonin level was modelled before or after treatment. ConclusionsAdministration of HT to postmenopausal women alters melatonin peak time, but not melatonin levels. Further research on larger clinical samples is needed to better understand the effects of HT on melatonin profile.

Decreased daily melatonin levels in women with systemic lupus erythematosus - a short report.

The neuroendocrine system is known to influence immunity, but the precise interactions between different hormones and autoimmune disorders remain obscure. The present study aimed to investigate the role of daily serum melatonin concentrations in the development of systemic lupus erythematosus (SLE) in women. Case-control study. One-hundred and eleven SLE female patients and 46 healthy women were included in the study. Daily serum melatonin levels were investigated in all participants. SLE patients showed significantly lower daily melatonin levels in comparison to healthy women during the short photoperiod (17.75±7.13 pg/mL [16.05] vs. 21.63±6.60 pg/mL [20.10], p=0.012). Hormone concentrations were inversely related to the SLE activity index (SLEDAI) (r= -0.268, p=0.004), but they did not correlate to any particular American College Rheumatology (ACR) criterion (p>0.05 for all). Daily melatonin levels were decreased in women with systemic lupus erythematosus and correlated inversely to the activity of the autoimmune disease. Further studies are needed to clarify the importance of the pineal and extrapineal melatonin secretion in patients with systemic lupus erythematosus as well as the interrelations between hormones and autoimmunity.

Serum Melatonin in Women with Polycystic Ovary Syndrome

There has been a surge of interest in recent years in studying the changes of serum melatonin concentrations in disorders that are associated with insulin resistance such as diabetes mellitus type 2 and polycystic ovary syndrome (PCOS). The present study was designed to investigate the day-time and night-time levels of serum melatonin and the cortisol rhythm in women with PCOS and compare them with those of healthy women. This is a case-control study which included 30 women with PCOS and 25 healthy women. All hormonal measurements in both the study group and controls were carried out between days 3 and 5 counted from the beginning of the last regular menstrual cycle; they included serum levels of melatonin and cortisol at 03:00 a.m and 08:00 a.m, total testosterone (T), dehydroepiandrosterone sulfate (DHEA-S), luteinizing hormone (LH), follicle stimulating hormone (FSH), and immunoreactive insulin at 08:00 a.m. Women with PCOS were found to have a significantly higher melatonin level at 08:00 a.m. and smaller mean night-day difference in the concentrations of melatonin in comparison with those of healthy women (natural log (Ln) night-day difference 0.60 +/- 0.10 pg/ml versus 1.15 +/- 0.14, p < 0.002). Melatonin to cortisol ratios at 03:00 a.m. and 08:00 a.m. showed no statistically significant differences between the two groups (Ln melatonin/cortisol 03:00 a.m., 1.01 +/- 0.06 versus 1.05 +/- 0.05; Ln melatonin/cortisol at 08:00 a.m., 0.62 +/- 0.01 versus 0.56 +/- 0.03, p > 0.05). The results we obtained about the changes of melatonin in women with PCOS could help in elucidating the complex pathophysiological pattern of this disease.

The Concept of the Immune-Pineal Axis Tested in Patients Undergoing an Abdominal Hysterectomy

Objective: Activation of the immune-pineal axis induces a transient reduction in nocturnal melatonin in the plasma during the proinflammatory phase of an innate immune response to allow the proper migration of leukocytes to the lesion site. This transient reduction should be regulated by inflammatory mediators, which are responsible for the fine-tuning of the process. In the present study, we measured the pre- and postoperative serum concentrations of melatonin, tumor necrosis factor (TNF) and cortisol in women who underwent an elective hysterectomy and correlated the variation in melatonin with postoperative pain. Methods: We evaluated 12 women who had an abdominal hysterectomy. Blood was collected at 10.00 and 22.00 h 1 week and 1 day before the surgery, on the 1st and 2nd days after the surgery and at 22.00 h on the day of the surgery. Results: On the night after the surgery, there was no melatonin detected at 22.00 h. High TNF levels were accompanied by a lower nocturnal melatonin output, higher postoperative pain according to a visual analog scale and the request of higher doses of analgesics. In addition, low cortisol levels were accompanied by a lower nocturnal melatonin output. Conclusion: Our results confirm that the same antagonistic pattern between TNF and glucocorticoids observed in cultured pineal glands also occurs in humans. This integrative pattern suggests that the cross talk between the immune and endocrine system orchestrates longitudinal changes in pineal activity, reinforcing the hypothesis of an immune-pineal axis.

Clinical significance of melatonin concentrations in predicting the severity of acute pancreatitis

To assess the value of plasma melatonin in predicting acute pancreatitis when combined with the acute physiology and chronic health evaluation II (APACHEII) and bedside index for severity in acute pancreatitis (BISAP) scoring systems. APACHEII and BISAP scores were calculated for 55 patients with acute physiology (AP) in the first 24 h of admission to the hospital. Additionally, morning (6:00 AM) serum melatonin concentrations were measured on the first day after admission. According to the diagnosis and treatment guidelines for acute pancreatitis in China, 42 patients suffered mild AP (MAP). The other 13 patients developed severe AP (SAP). A total of 45 healthy volunteers were used in this study as controls. The ability of melatonin and the APACHEII and BISAP scoring systems to predict SAP was evaluated using a receiver operating characteristic (ROC) curve. The optimal melatonin cutoff concentration for SAP patients, based on the ROC curve, was used to classify the patients into either a high concentration group (34 cases) or a low concentration group (21 cases). Differences in the incidence of high scores, according to the APACHEII and BISAP scoring systems, were compared between the two groups. The MAP patients had increased melatonin levels compared to the SAP (38.34 ng/L vs 26.77 ng/L) (P = 0.021) and control patients (38.34 ng/L vs 30.73 ng/L) (P = 0.003). There was no significant difference inmelatoninconcentrations between the SAP group and the control group. The accuracy of determining SAP based on the melatonin level, the APACHEII score and the BISAP score was 0.758, 0.872, and 0.906, respectively, according to the ROC curve. A melatonin concentration ≤ 28.74 ng/L was associated with an increased risk of developing SAP. The incidence of high scores (≥ 3) using the BISAP system was significantly higher in patients with low melatonin concentration (≤ 28.74 ng/L) compared to patients with high melatonin concentration (> 28.74 ng/L) (42.9% vs 14.7%, P = 0.02). The incidence of high APACHEII scores (≥ 10) between the two groups was not significantly different. The melatonin concentration is closely related to the severity of AP and the BISAP score. Therefore, we can evaluate the severity of disease by measuring the levels of serum melatonin.

In vivo response of melatonin, gonadal activity and biochemical changes during CYP19 inhibited sex reversal in common carp Cyprinus carpio (L)

CYP19 aromatase is the key enzyme in vertebrate steroidogenesis, catalyzing the conversion of C19 androgens to 17β-estradiol (E2). The objective of the present study was to assess the effect of the CYP19 inhibitors (AIs) fadrozole and anastrozole on gonadal development and sex differentiation in Cyprinus carpio and investigate the possible involvement of in vivo melatonin (MLT) production during sex differentiation. The CYP19 activity in 30 day-post fertilized (30 dpf) fingerlings was inhibited by treating with fadrozole and anastrozole in doses of 100mg/kg and 200mg/kg of feed. Gonado-somatic-index (GSI) of fish decreased (P<0.005) and the changes in GSI was dose dependent. Serum testosterone (T) concentration increased (P<0.001) after AI treatments and was negatively correlated with serum E2 concentration which decreased (P<0.005). Morning serum MLT concentration decreased during the period of inhibited CYP19 activity with a positive correlation with E2 concentration. Sex-ratio in anastrazole (200mg/kg) treated fish were 98.1% males while with fadrozole treatment at the same dose resulted in a 97.1% masculinization. Histological examination of fadrozole-treated fish gonads resulted in detection of atretic follicles and intensified spermiation. The protein and lipid production was depressed in AIs-treated fish. The results suggested that fadrozole and anastrozole both effectively inhibited oogenesis and ovarian development in C. carpio accelerating testicular formation. There was a physiological correlation between CYP19 activity, E2 and MLT synthesis during gonadal development and sex differentiation.

Serum melatonin levels and antioxidant capacities after consumption of pineapple, orange, or banana by healthy male volunteers

Melatonin is a naturally occurring molecule biosynthesized by the pineal gland of vertebrates; it also has been identified in many plants. It is considered an important antioxidant and may retard the development of some neurodegenerative diseases and cancer. Previous studies in humans have measured melatonin metabolites in urine and have indicated that melatonin-containing foods may provide dietary melatonin. This study tested whether the consumption of fruits or fruit juice containing melatonin would influence the serum melatonin concentration and antioxidant status. In this crossover study, 12 healthy male volunteers took either juice extracted from one kilogram of orange or pineapple or two whole bananas, with a 1-wk washout period between the fruit or fruit juices. An enzyme-linked immunosorbent (ELISA) assay was used to determine the serum melatonin concentration. Serum antioxidant capacity was determined by ferric reducing antioxidant power (FRAP) assay and oxygen radical antioxidant capacity (ORAC) assay. The highest serum melatonin concentration was observed at 120min after fruit consumption, and compared with before consumption levels, their values were significantly increased for pineapple (146 versus 48pg/mL P=0.002), orange (151 versus 40pg/mL, P=0.005), and banana (140 versus 32pg/mL, P=0.008), respectively. Serum antioxidant capacity following fruit consumption also significantly increased in both the FRAP (7-14% increase, P≤0.004) and ORAC (6-9% increase, P=0.002) assays. Both the serum FRAP and ORAC values strongly correlated with serum melatonin concentration for all three fruits. These findings suggest that tropical fruit consumption increases the serum melatonin concentrations and also raises the antioxidant capacity in the serum of healthy volunteers in proportion to serum melatonin levels.

Pineal arylalkylamine N-acetyltransferase (Aanat) gene expression as a target of inflammatory mediators in the chicken

Previously, we demonstrated that experimental peritonitis in chickens was attenuated by treatment with exogenous melatonin, while the developing inflammation decreased pineal AANAT activity. This suggested the existence of a bidirectional relationship between the activated immune system and pineal gland function. The aim of the present study was to identify the step(s) in the chicken pineal melatonin biosynthetic pathway that are affected by inflammation. Peritonitis was evoked by i.p. injection of thioglycollate solution, either 2h after the start, or 2h before the end of the light period, and the animals were sacrificed 4h later. The effect of inflammation on the expression of genes encoding enzymes participating in melatonin biosynthesis in the pineal gland, i.e. tryptophan hydroxylase 1 (Tph1), dopa decarboxylase (Ddc), arylalkylamine N-acetyltransferase (Aanat) and acetylserotonin O-methyltransferase (Asmt), was evaluated by qPCR. The pineal and serum melatonin concentration as well as the content of its precursors in the pineal gland were measured, along with the activity of the relevant biosynthetic enzymes. Developing peritonitis caused an increase in the pineal levels of the Tph1 mRNA during the night and the Asmt mRNA during the day, while nocturnal Aanat transcription was reduced. Both the pineal and serum melatonin level and the pineal content of N-acetylserotonin (NAS) were decreased during the night in birds with peritonitis. The amount and activity of pineal AANAT were significantly reduced, while the activity of HIOMT was increased under these experimental conditions. These results indicate that the observed decrease in MEL biosynthesis in chickens with developing inflammation is a result of transcriptional downregulation of the Aanat gene, followed by reduced synthesis and activity of the encoded enzyme.

High Endogenous Melatonin Levels in Critically Ill Children: A Pilot Study

To evaluate the serum melatonin levels in critically ill pediatric patients and to test the effect of light on the melatonin's circadian rhythm. Data on melatonin secretion in critically ill pediatric subjects are lacking. We investigated the serum melatonin levels of 16 sedated and mechanically ventilated patients in a pediatric intensive care unit. Children (mean age, 5.1 ± 3.1 years) were randomly assigned to a dark-exposed or to a light-exposed group to evaluate the effects of light on serum melatonin concentrations. Blood samples for serum melatonin analysis were collected at 10 p.m., 1 a.m., 3 a.m., 5 a.m., 8 a.m., and 12 p.m. The melatonin circadian rhythm was severely disrupted in critically ill children; light exposure lowered serum melatonin even in a context of highly altered circadian cycle; melatonin peaks were greater for healthy age-matched children. The high melatonin levels in the critically ill children may be a response to counteract the elevated oxidative stress associated with serious diseases. Whether these elevated melatonin levels confer any beneficial effects in pediatric critically ill patients remains unknown.

Decreased level of melatonin in serum predicts left ventricular remodelling after acute myocardial infarction

As experimental studies suggest that melatonin is cardioprotective after myocardial infarction (MI), this study sought to investigate the relationships between circulating levels of melatonin and left ventricular (LV) remodelling in patients after acute MI. This prospective study included 161 patients (age 61±3yr; 78% men) undergoing primary percutaneous coronary intervention who were assessed echocardiographically at hospital discharge (day 3-7) and at 12 months. LV remodelling was defined as >20% increase in LV end-diastolic volume at 12-month follow-up compared with baseline. Serum melatonin concentrations were measured at admission, during the light period. Twenty-four patients showed LV remodelling, and 137 had no evidence of LV remodelling. Patients with LV remodelling had lower levels of melatonin at study entry [9.96 (8.28-11.03) versus 16.74 (13.77-19.59) pg/mL, respectively; P <0.0001]. Multivariate analysis showed that melatonin levels (OR=2.10, CI 95% 1.547-2.870, P<0.001) were an independent predictor of LV remodelling at 12-month follow-up. Receiver operating characteristic (ROC) analysis showed an area under the curve of 0.959 (CI 95% 0.93-0.98; P<0.0001). To our knowledge, this is the first study to show the relationship between melatonin and LV remodelling during the chronic phase post-MI.

Effects of tryptophan supplementation on cashmere fiber characteristics, serum tryptophan, and related hormone concentrations in cashmere goats

This study was designed to investigate the effects of tryptophan (Trp) supplementation on cashmere fiber characteristics and on serum Trp, melatonin (MEL), prolactin (PRL), insulin-like growth factor 1 (IGF-1), triiodothyronine (T3), and thyroxine (T4) concentrations in cashmere goats during the cashmere fast-growth period. Thirty-six Liaoning cashmere wether goats were stratified on the basis of body weight (28 ± 0.8 kg) and assigned randomly to 1 of the following 4 rumen-protected Trp treatments: 0, 2.0, 4.0, and 6.0 g per goat per day. The experimental period lasted 137 d. Blood samples were collected monthly during the daytime (8:00 AM) and at night (8:00 PM). Tryptophan supplementation improved cashmere growth rates, cashmere weight, and body weight (P = 0.001) and increased serum Trp levels, nighttime MEL concentrations, IGF-1, and T3 and T4 concentrations (P < 0.05). Across the treatments and sampling months, a highly positive correlation between cashmere growth rate and nighttime serum MEL concentrations was observed (r = 0.879, P = 0.001). A moderately negative correlation between cashmere growth rates and serum PRL concentrations during the day and at night (rday = –0.645, P = 0.007; rnight = –0.583, P = 0.018) was observed. A moderately positive correlation between the cashmere growth rate and the daytime serum IGF-1 concentration (r = 0.536, P = 0.032) was observed, and no correlation was found between the cashmere growth rate and the other serum hormone concentrations. These data indicate that changes in serum concentrations of MEL, IGF-1, and PRL are related to cashmere growth in Liaoning cashmere goats during the cashmere fast-growth period. Under the experimental conditions of the current trial, we suggest that Trp may promote cashmere growth by increasing daytime IGF-1 and nighttime MEL secretion.

Abnormal circadian rhythm of melatonin in Smith–Magenis syndrome patients with RAI1 point mutations

Abnormal circadian rhythm of melatonin in Smith–Magenis syndrome patients with <i>RAI1</i> point mutations

The effect of neuroleptic drugs on serum and cerebrospinal fluid melatonin concentrations in psychiatric subjects.

Journal Article The effect of neuroleptic drugs on serum and cerebrospinal fluid melatonin concentrations in psychiatric subjects Get access J A Smith, J A Smith Department of Pharmaceutical Chemistry, University of Bradford Correspondence: Ida Darwin Hospital, Fulbourn, Cambridge, U.K. Search for other works by this author on: Oxford Academic Google Scholar J L Barnes, J L Barnes Department of Pharmaceutical Chemistry, University of BradfordIda Darwin Hospital, Fulbourn, Cambridge, UK Search for other works by this author on: Oxford Academic Google Scholar T J Mee T J Mee Department of Pharmaceutical Chemistry, University of Bradford Search for other works by this author on: Oxford Academic Google Scholar Journal of Pharmacy and Pharmacology, Volume 31, Issue 1, September 1979, Pages 246–248, https://doi.org/10.1111/j.2042-7158.1979.tb13488.x Published: 12 April 2011 Article history Received: 19 May 1978 Published: 12 April 2011

Elevated melatonin serum concentrations in psychiatric patients treated with chlorpromazine [proceedings

Elevated melatonin serum concentrations in psychiatric patients treated with chlorpromazine [proceedings

Secretion of melatonin and 6-sulfatoxymelatonin urinary excretion in functional dyspepsia

To evaluate blood concentration of melatonin and urinary excretion of its metabolite, 6-sulfatoxymelatonin (6-OHMS), in functional dyspepsia (FD). Ninety individuals were enrolled in the study: 30 in each study group: patients with postprandial distress syndrome (PDS), epigastric pain syndrome (EPS), and controls. Blood samples were drawn at 02:00 and 09:00 h and 24-h urine collection was performed. Serum melatonin and urinary 6-OHMS concentrations were measured by enzyme-linked immunosorbent assay. Serum melatonin concentration at night and in the morning was significantly (P < 0.001) higher in PDS patients [at 02:00 h-93.3 pg/mL, quartile range (QR): 79.8-116.2; at 09.00 h-14.3 pg/mL, QR: 7.06-19.0] than in EPS (57.2 pg/mL, QR: 42.6-73.1; 8.1 pg/mL, QR: 4.1-9.3) and control patients (57.7 pg/mL, QR: 51.2-62.5; 8.1 pg/mL, QR: 5.4-10.3). A similar relationship was observed for urinary 6-OHMS excretion. Patients with severe PDS symptoms had a higher melatonin concentration than these with moderate syndromes, whereas patients with severe EPS had a lower urinary 6-OHMS excretion than patients with moderate symptoms. Evaluation of melatonin serum concentrations and 24-h urinary 6-OHMS excretion are useful methods for differential diagnosis of various clinical forms of FD.