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Journal Article 2003; 24(6): 392-396 PubMed PMID: 15073562 Citation  Keywords:  Animals, Circadian Rhythm, Male, Melatonin:blood, Models, Animal, Pineal Gland:secretion, Postoperative Complications:metabolism, Pressure, Rats, Rats, Sprague-Dawley, Surgical Instruments,.   

OBJECTIVES: Pineal gland hormone, melatonin, is a current issue of interest for accumulating data concerning its diverse physiological functions. The disturbances in melatonin secretion are observed in different pathological conditions involving pineal regions, but it is not ascertained if those disturbances present any clinical implications. The aim of this work was to examine whether pineal gland compression changes melatonin secretion.

SETTING AND DESIGN: The experiment was carried out on adult rats, divided into four equal groups: (i) control (no surgery was performed), (ii) sham-operated, (iii) with sham pineal gland compression and (iv) with pineal gland compression performed by cotton piece application.

METHODS: The profile of melatonin secretion was assessed in blood samples collected five times daily, every second day, starting from 8 to 14 day following surgery.

RESULTS: We found that surgery itself significantly increased night melatonin secretion in comparison to controls. By contrast, in pineal-gland compressed rats, melatonin secretion was lower than in control group, suggesting that the influence of pineal compression overcame that induced by operation stress.

CONCLUSIONS: In conclusion, we presume that pineal gland compression (like in case of some tumors) results in decrease of the concentration of blood melatonin, that may possibly result in decreased protective action of the indoleamine....

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Journal Article 2003; 24(3-4): 181-184 PubMed PMID: 14523354 Citation  Keywords:  Adult, Biomarkers, Circadian Rhythm:physiology, Humans, Male, Melatonin:blood, Psychiatric Status Rating Scales, Schizophrenia:blood, Schizophrenic Psychology,.   

OBJECTIVE: Aim of this study was to verify if a simple index as night-day plasma MLT level variation is able to confirm the existing data on circadian melatonin alterations in schizophrenia and if a relationship to disease itself instead of the actual clinical state can be suggested.

SETTING AND DESIGN: Ten consecutively admitted male schizophrenic inpatients were examined.

METHODS: The blood samples for melatonin were collected at 3.00 a.m. and 15.00 p.m. and consequently calculated the values of Delta () (MLT h.3.00- MLT h.15.00). We divided the sample into two subgroups: < 30 pg/ml and > 30 pg/ml taking 30 pg/ml as an arbitrary value, based on literature data, that should indicate a physiologically correct value of.

RESULTS: The 70% of the sample was under the 30 pg/ml value of (13.61 +/- 4.0) or was lacking of the characteristic circadian pattern of MLT secretion, whilst the 30% of the sample was over the 30 pg/ml value of (83.60 +/- 16.34) or was in presence of the characteristic circadian pattern of MLT secretion (p=.0001). No correlation was found between values and the scale and subscales scores for the assessment of psychopathology.

MAIN FINDINGS: The data confirm the lack of the characteristic circadian pattern of MLT secretion in schizophrenics.

CONCLUSION: The absence of significant correlation between night / day melatonin level differences and actual psychopathology variables should indicate that the suppression of is mostly related to the disease and independent from the clinical state. A neuroleptic-treatment effect cannot be excluded so far....

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Journal Article 2002; 23(3): 239-242 PubMed PMID: 12080285 Citation  Keywords:  Adenocarcinoma:metabolism, Aged, Circadian Rhythm, Colorectal Neoplasms:metabolism, Female, Humans, Male, Melatonin:blood, Middle Aged, Radioimmunoassay,.   

OBJECTIVE: The aim of the study was pineal gland function assessment on the base of daily rhythm study and mean daily melatonin (MEL) concentrations in serum in patients with colorectal carcinoma.

MATERIAL AND METHODS: Studies were performed in 12 women at the age of 63.17+/-5.90 years and 21 men aged 58.95+/-11.32 years with large intestine adenocarcinoma. The control group consisted of 28 healthy volunteers at comparable age. During the circadian study blood samples for the measurement of melatonin (MEL) were collected every 4 hours during 12 h. MEL concentrations were assessed with the use of RIA methods. Statistical analysis of circadian rhythms of MEL was carried out with the use of cosinor method according to Halberg.

RESULTS: Existence of daily rhythm of MEL secretion was shown in all studied groups. A significant decrease of amplitude of rhythm and secretion of MEL at nocturnal hours in comparison with the control group was shown in the group of women with large intestine carcinoma. A significant decrease of mesor value and amplitude of MEL rhythm as a consequence of decrease of MEL secretion at nocturnal and morning hours was observed in the group of ill men.

CONCLUSIONS: Decrease in melatonin circadian rhythm amplitude as a consequence of its lowered nocturnal secretion occurred in all patients with colorectal carcinoma. Abnormalities in daily rhythm of melatonin secretion were more intensified in men with large intestine carcinoma, which leads to suppression of mean daily hormone concentration....

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Clinical Trial 2002; 23(3): 213-217 PubMed PMID: 12080281 Citation  Keywords:  Adult, Body Temperature:drug effects, Circadian Rhythm:drug effects, Humans, Male, Melatonin:blood, Pineal Gland:drug effects, Pyridoxine:administration & dosage, Sleep:drug effects,.   

OBJECTIVES: To determine pineal response to pyridoxine in normal men.

MATERIAL AND METHODS: Twelve healthy men were given orally pyridoxine (100 mg) or placebo at 1700h. Serum melatonin levels were determined every 30 minutes with simultaneous measurement of core body temperature between 1700h to 0300h. Polysomnographic sleep recordings were performed between 1800h to 2000h.

RESULTS: Serum melatonin levels after both placebo and pyridoxine showed a nocturnal rise occurring at 22:10+/-1:22h and 22:24+/-1:09h, respectively. The melatonin onset, peak, mean and area under the curve (AUC) values after pyridoxine (3.2+/-1.6 pg/ml, 47.2+/-22.6 pg/ml, 31.5+/-11.0 pg/ml and 173.5+/-138.4 pg/ml x min, respectively) were similar to the values after placebo administration (4.7+/-1.6 pg/ml, 53.9+/-26.0 pg/ml, 37.2+/-2.8 pg/ml and 205.3+/-137.8 pg/ml x min, respectively). CBT revealed a significant nocturnal decline but without significant difference between pyridoxine and placebo. Sleep amount and architecture were similar after the two treatments.

CONCLUSIONS: In adult man, the oral administration of 100 mg-pyridoxine during the evening hours has no effect on melatonin secretion nor does it alter CBT or sleep quality....

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Clinical Trial 2002; 23(Suppl 1): 97-102 PubMed PMID: 12019361 Citation  Keywords:  Adult, Blood Pressure:physiology, Circadian Rhythm:physiology, Creatinine:urine, Disease Progression, Female, Humans, Kidney Failure, Chronic:blood, Male, Melatonin:blood, Middle Aged, Urea:metabolism,.   

OBJECTIVES: In spite of broad interest, intensive studies on function of melatonin have not yielded much information about relationships between this hormone and kidneys in health, and particularity, in disease. Very little is known about the circadian plasma melatonin concentrations in patients with chronic renal failure (CRF). There are only a few studies dealing with melatonin concentrations in renal diseases, mainly performed in hemodialyzed patients with end-stage renal disease (ESRD). Moreover, the most melatonin assays were performed during the daytime, and the results are conflicting. Therefore, the aim of the present study was to determine the circadian melatonin profiles in patients with different stages of CRF.

MATERIAL AND METHODS: Twenty four patients (13 males and 11 females) with CRF aged 35 to 58 years (mean+/-SEM: 47.0+/-1.6 years) were included in the study. Patients were divided into two groups: group 1 -- patients with compensated CRF (serum creatinine: 2.0-5.0 mg/dL), group 2 -- patients with ESRD (serum creatinine: > 8,0 mg/dL). The control group consisted of 20 healthy volunteers (10 males and 10 females) aged 35 to 55 years (mean+/-SEM: 46.0+/-1.5 years) checked not to have renal failure [serum creatinine: 0.8-1.4 mg/dL], and matched according to sex and age. Blood samples were collected at 08:00, 12:00, 16:00, 20:00, 24:00, 02:00, 04:00, and 08:00 h. Melatonin concentration was measured by enzyme immunoassay.

RESULTS: In both groups of patients with chronic renal failure, i.e. in patients with compensated disease and in patients with end-stage renal disease melatonin nocturnal concentrations were significantly lower then those in healthy volunteers. Moreover, in patients with compensated renal failure also day-time melatonin concentrations were significantly depressed. Area under curve was significantly lower in both groups of patients in comparison with the control group.

CONCLUSIONS: The mechanism of depressed melatonin concentrations in CRF observed in our study remains unclear. However, it seems possible that decline in melatonin levels is due to impairment in adrenergic function that occurs in CRF. Because the studies on the melatonin secretion in CRF bring about conflicting results, the relationship between renal diseases and melatonin secretion needs further investigations....

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Journal Article 2002; 23(Suppl 1): 92-96 PubMed PMID: 12019360 Citation  Keywords:  Diagnosis, Humans, Melatonin:blood, Neoplasms:blood, Pineal Gland:metabolism, Prognosis, Tissue Distribution,.   

: During the last decade, attention was concentrated on melatonin -- one of the hormones of the diffuse neuroendocrine system, which has been considered only as a hormone of the pineal gland, for many years. Currently, melatonin has been identified not only in the pineal gland, but also in extrapineal tissues -- retina, harderian gland, gut mucosa, cerebellum, airway epithelium, liver, kidney, adrenals, thymus, thyroid, pancreas, ovary, carotid body, placenta and endometrium as well as in non-neuroendocrine cells like mast cells, natural killer cells, eosinophilic leukocytes, platelets and endothelial cells. The above list of the cells storing melatonin indicates that melatonin has a unique position among the hormones of the diffuse neuroendocrine system, which is present in practically all organ systems. Functionally, melatonin-producing cells are certain to be part and parcel of the diffuse neuroendocrine system as a universal system of response, control and organism protection. Taking into account the large number of melatonin-producing cells in many organs, the wide spectrum of biological activities of melatonin and especially its main property as a universal regulator of biological rhythms, it should be possible to consider extrapineal melatonin as a key paracrine signal molecule for the local coordination of intercellular relationships. Analysis of our long-term clinical investigations shows the direct participation and active role of extrapineal melatonin in the pathogenesis of tumor growth and many other non-tumor pathologies such as gastric ulcer, immune diseases, neurodegenerative processes, radiation disorders, etc. The modification of antitumor and other specific therapy by the activation or inhibition of extrapineal melatonin activity could be useful for the improvement of the treatment of illness....

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Journal Article 2001; 22(4): 251-254 PubMed PMID: 11524632 Citation  Keywords:  Aging:physiology, Animals, Circadian Rhythm, Endocrine System Diseases:drug therapy, Female, Macaca mulatta, Melatonin:blood, Nervous System Diseases:drug therapy, Oligopeptides:therapeutic use, Osmolar Concentration,.   

UNLABELLED: The OBJECTIVE of this research was to investigate the regulatory effect of Epitalon on the production of melatonin and cortisol in senescent monkeys.

MATERIAL AND METHODS: We investigated the character of melatonin and cortisol secretion by immunoferment assay in Epitalon-administered female Macaca mulatta in different age periods.

RESULTS: Epitalon was proven to significantly stimulate melatonin synthesis in senescent monkeys in the evening, thereby normalising the circadian rhythm of cortisol secretion....

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Journal Article 2001; 22(3): 192-198 PubMed PMID: 11449197 Citation  Keywords:  Adult, Affect, Antidepressive Agents:therapeutic use, Circadian Rhythm, Clomipramine:therapeutic use, Depression:blood, Female, Humans, Male, Melatonin:blood, Middle Aged, Sleep Wake Disorders:complications,.   

OBJECTIVES: The aim of the study was to establish if there are differences in the 24-hour melatonin secretion profile between patients with major depression (before, and after treatment with clomipramine) compared to those in healthy subjects. Additionally, we determined if there are differences in melatonin concentrations, depending on the severity of depression, and the presence of 24-hour rhythm disturbances.

MATERIAL AND METHODS: Twenty patients with major depression and 24-hour rhythm disturbances, and 14 healthy volunteers took part in the study. Before, and after treatment with clomipramine all subjects had blood samples collected at 08:00, 14:00, 20:00, 24:00, 02:00, 04:00, and 08:00 h, for estimation of melatonin concentrations. Before and after treatment, the severity of depression was evaluated using the following scales: the Hamilton Depression Rating Scale (HADRS), Beck Depression Inventory (BDI), and clinical observation, as well as presence, and if so, severity of 24-hour rhythm disturbances were assessed.

RESULTS: In individuals with major depression with marked disturbances of their diurnal rhythms, melatonin secretion is also disturbed, shown by the higher melatonin concentrations at night as compared to those in healthy individuals. However, melatonin levels were independent of the severity or the clinical manifestation of depression. Moreover, no correlation between the disturbances in their diurnal rhythms (sleep-watchfulness, diurnal mood shifts) and disturbed melatonin pattern was observed.

CONCLUSIONS: Melatonin nocturnal concentrations in patients with major depression were higher than those in healthy individuals. However, the melatonin concentration values do not differentiate the patients in terms of the severity of the depressive symptoms....

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