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Controlled Clinical Trial 2008; 29(1): 168-172 PubMed PMID: 18283250 Citation  Keywords:  Adult, Affect:physiology, Anorexia Nervosa:physiopathology, Appetite:physiology, Body Temperature:physiology, Bulimia Nervosa:physiopathology, Circadian Rhythm:physiology, Eating:physiology, Female, Humans, Hunger:physiology, Phototherapy:methods,.   

OBJECTIVES: Light and food are important synchronizers of circadian rhythmicity. In eating disorders, the circadian rhythms of food intake and temperature are abnormal.

METHODS: We analyzed the effect of the morning light application on the circadian rhythm of tympanic temperature and its association with hunger and mood changes in the sample of 25 female patients hospitalized with DSM-IV diagnosis of eating disorders (14 bulimia nervosa and 11 anorexia nervosa) and in 6 healthy women.

RESULTS: Light therapy reduced interindividual variability of the temperature acrophase, synchronized the temperature and hunger rhythms and showed an antidepressant effect on patients with eating disorders. Bright light therapy normalized the circadian rhythm of body temperature in both anorexic and bulimic patients: phase advanced rhythm was delayed and phase delayed rhythm was advanced. In contrast with anorexic patients, the majority of bulimic patients had normal temperature rhythm before the therapy and this rhythm was not changed by the therapy.

CONCLUSION: The light therapy normalized temperature circadian rhythm in patient with eating disorders. We hypothesize that the light therapy can also contribute to improvement of pathological eating pattern because of the functional connections between light and food entrained oscillators. The light may help to restore the irregular circadian rhythmicity induced by chaotic food intake....

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Journal Article 2005; 26(4): 301-304 PubMed PMID: 16136022 Citation  Keywords:  Adolescent, Amenorrhea:blood, Anorexia Nervosa:blood, Appetite:physiology, Body Weight:physiology, Child, Energy Intake, Estradiol:blood, Female, Follicle Stimulating Hormone:blood, Humans, Hydrocortisone:blood, Leptin:blood, Luteinizing Hormone:blood, Ne.   

OBJECTIVES: The pathogenesis of anorexia nervosa (AN) remains still unclear. It has been reported that neuropeptides may play a role in the control of appetite and hormone release contributing to hormonal disturbances in AN. However the question if neuropeptide alterations are consequence or cause of malnutrition is still unresolved.

METHODS: Serum leptin, neuropeptide Y (NPY) concentrations as well as hormones (FSH, LH, estradiol, cortisol and fT4) serum levels were prospectively estimated in 19 girls aged 11.7-17.7 years (mean 15.5 years) with anorexia nervosa (AN) at the admission to the hospital (baseline) and at follow-up after 7.21+ 2.32 months of treatment. The treatment consisted of hypercaloric diet, psychotherapy and vitamins supplementation.

RESULTS: Mean leptin concentration significantly increased from 7.99 + 2.6 to 9.98 + 2.48 microg/ml (p<0.01), whereas mean NPY concentration significantly decreased from 34.10 + 9.81 to 29.6 + 8.04 pmol/l (p<0.01). Leptin/BMI ratio was constant, while NPY/BMI ratio decreased. There were no significant differences between leptin and NPY serum concentrations at baseline and follow-up in eumenorrheic vs. amenorrheic patients. Simple linear correlation analysis showed negative correlation between leptin and NPY concentrations at baseline (r=-0.67; p<0.05) and at follow-up (r=-0.76; p<0.05) only in eumenorrheic subgroup. There were no significant correlations between leptin, NPY and BMI and body weight values.

CONCLUSIONS: 1) Serum concentration of leptin increases and serum concentration of NPY decreases significantly during the treatment of anorectic girls. 2) These changes do not correspond with increasing body weight and BMI suggesting disregulation of appetite and body weight control mechanisms in AN. 3) Altered neuroregulation of the neuropeptides (leptin and NPY) secretion may contribute persistent amenorrhea after weight gain in anorectic patients with low initial BMI....

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Journal Article 2005; 26(4): 289-292 PubMed PMID: 16135995 Citation  Keywords:  Animals, Appetite:physiology, Humans, Intracellular Signaling Peptides and Proteins:physiology, Narcolepsy:physiopathology, Neuropeptides:physiology, Neurosecretory Systems:physiology, Orexins, Sleep:physiology, Wakefulness:physiology,.   

: Orexins/hypocretins are recently discovered neuropeptides synthetized mainly by neurons located in the posterolateral hypothalamus. Hypocretin-1 and -2 are the same peptides as orexin-A and orexin-B. Orexin A is a 33 amino acid peptide with N-terminal pyroglutamyl residue and two intrachain disulphide bonds. Orexin B is a linear peptide of 28 amino acids. These two peptides are potent agonists at both the orexin-1 (OxR1) and orexin-2 (OxR2) receptors. Orexin-A is selective ligand for OxR1 and OX2 binds both orexins. The structure of orexins and their receptors is highly conservative in mammals. Orexin A sequence is identical in several mammalian species (human, mouse, rat, bovine and porcine). Intracerebroventricular administered orexin-A stimulates food intake and energy expenditure. Orexins are also involved in the regulation of neurohormones and pituitary hormones secretion as well as in the control of cardiovascular and sleep-wake function. Orexins also play a role in the pathogenesis of narcolepsy. Mutation in the gene coding preproorexin or OxR2 receptor gene results in narcolepsy in mice and canine. In patients with narcolepsy orexin neurotransmission was altered and orexin level in cerebrospinal fluid was undetectable....

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Journal Article 2003; 24(6): 431-434 PubMed PMID: 15073570 Citation  Keywords:  Adult, Anorexia Nervosa:metabolism, Appetite:physiology, Diabetes Mellitus:metabolism, Feedback, Physiological, Female, Glucose Tolerance Test, Human Growth Hormone:metabolism, Humans, Hypertension:metabolism, Leptin:blood, Luteinizing Hormone:metabolism,.   

OBJECTIVE: It has been reported that neuropeptides may play a role in the control of appetite and in the mechanism of hormone release. Neuropeptides such as beta-endorphin, neuropeptide Y (NPY), galanin and leptin may affect hormones release, on the other hand the hormonal status may modulate neuropeptide activity.

METHODS: The material consisted of 90 obese women, 30 women with Anorexia Nervosa, and 30 healthy, lean women of control group. Plasma beta-endorphin, NPY, leptin, somatostatin and serum pituitary and gonadal hormones concentrations were measured with RIA methods.

RESULTS: We observed the highest plasma NPY levels in obese hypertensive and diabetic patients. After carbohydrate administration (OGTT) a marked increase of insulin, beta-endorphin and NPY was found. The blunted response of GH to GH-RH may be connected with increased somatostatin activity and hyperinsulinemia. The abnormal response of LH to opioid blockade may be a result of disturbed opioid and NPY activities in obese patients. However in patients with anorexia nervosa, plasma leptin and NPY concentrations were low. The disturbances in beta-endorphin release are also observed.

CONCLUSIONS: The neuroendocrine disturbances in obesity and in anorexia nervosa are opposite. The feedback mechanism between leptin and NPY is disturbed in both in obesity and in anorexia nervosa. An abnormal activity of neuropeptides may lead to disturbed control of appetite and hormonal dysregulation in eating disorders....

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