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Seasonal affective disorder: Lower or raised resting metabolic rate?
Medical Hypotheses
J
I Ma&a Hypoumaa~ (1993) 40,367 0 L&mpm Gmup UK L&l 1993
Seasonal Affective Disorder: Lower or Raised Resting Metabolic Rate? E. P. HELENIAK 811 Madison Ave, Dunellen, NJ 08812, USA
Abstract-Patients with seasonal affective disorder (SAD) were predicted to have low resting metabolic rates (RMR). However, studies have revealed that SAD patients have significantly higher RMR values. Increased melatonin may explain it.
Introduction Paul Gast et al (1) reported that symptoms of seasonal affective disorder (SAD) could be construed as having an energy conserving function. Their prediction is that SAD patients would have abnormally low RMR which would be increased to normal levels by light therapy. Contrary to their predictions, their research revealed that SAD patients have significantly higher RMR values and these values were significantly lowered with light therapy. They could not explain it. Conclusion In a paper (2) I published in 1989, Prostaglandins, Brown Fat and Weight Loss, I discussed the probable cause of increased RMR in SAD. Many studies indicate melatonin is increased in SAD. Evidence implicates the pineal in thermoregulation since melatonin has been found to stimulate brown adipose tissue (BAT). Short day (less light) plus cold exposure (winter time) results in a positive response to norepinephrine. Non-shivering thermogenesis is stimulated with an elevation of metabolic rate above the basal level. Evidence now indicates that postganglionic symDate received 4 August 1992 Date accepted 28 September 1992
pathetic neurons constitute in the rat the final common pathway for control of melatonin synthesis by environmental lighting (light inhibits melatonin formation). Incidentally, administration of indomethacin (an inhibitor of prostaglandin synthesis) in rats markedly decreases the night time activation of pineal serotonin N acetyl transferase, a key enzyme in melatonin synthesis. This indicates a role for prostaglandins in the regulation of pineal activity. Hyperphagia is increased by cold (non-shivering thermogenesis) and is responsible for the increase in appetite and weight. The ingestion (craving) of carbohydrates increases (via insulin) the transport of hyptophan (precursor of serotonin and melatonin) into the brain. Thus, melatonin increased by short photoperiods and cold is responsible for the elevation of metabolic rate above basal level. References 1. Gast P et al. Effects of bright light on resting metabolic rate in patients with seasonal affective disorder and control subjects. Biology Psychiatry 28: 989-996, 1990. 2. Heleniak E P, Aston B. Prostaglandins, brown fat and weight loss. Medical Hypotheses 28: 13-33, 1989.
J
I Ma&a Hypoumaa~ (1993) 40,367 0 L&mpm Gmup UK L&l 1993
Seasonal Affective Disorder: Lower or Raised Resting Metabolic Rate? E. P. HELENIAK 811 Madison Ave, Dunellen, NJ 08812, USA
Abstract-Patients with seasonal affective disorder (SAD) were predicted to have low resting metabolic rates (RMR). However, studies have revealed that SAD patients have significantly higher RMR values. Increased melatonin may explain it.
Introduction Paul Gast et al (1) reported that symptoms of seasonal affective disorder (SAD) could be construed as having an energy conserving function. Their prediction is that SAD patients would have abnormally low RMR which would be increased to normal levels by light therapy. Contrary to their predictions, their research revealed that SAD patients have significantly higher RMR values and these values were significantly lowered with light therapy. They could not explain it. Conclusion In a paper (2) I published in 1989, Prostaglandins, Brown Fat and Weight Loss, I discussed the probable cause of increased RMR in SAD. Many studies indicate melatonin is increased in SAD. Evidence implicates the pineal in thermoregulation since melatonin has been found to stimulate brown adipose tissue (BAT). Short day (less light) plus cold exposure (winter time) results in a positive response to norepinephrine. Non-shivering thermogenesis is stimulated with an elevation of metabolic rate above the basal level. Evidence now indicates that postganglionic symDate received 4 August 1992 Date accepted 28 September 1992
pathetic neurons constitute in the rat the final common pathway for control of melatonin synthesis by environmental lighting (light inhibits melatonin formation). Incidentally, administration of indomethacin (an inhibitor of prostaglandin synthesis) in rats markedly decreases the night time activation of pineal serotonin N acetyl transferase, a key enzyme in melatonin synthesis. This indicates a role for prostaglandins in the regulation of pineal activity. Hyperphagia is increased by cold (non-shivering thermogenesis) and is responsible for the increase in appetite and weight. The ingestion (craving) of carbohydrates increases (via insulin) the transport of hyptophan (precursor of serotonin and melatonin) into the brain. Thus, melatonin increased by short photoperiods and cold is responsible for the elevation of metabolic rate above basal level. References 1. Gast P et al. Effects of bright light on resting metabolic rate in patients with seasonal affective disorder and control subjects. Biology Psychiatry 28: 989-996, 1990. 2. Heleniak E P, Aston B. Prostaglandins, brown fat and weight loss. Medical Hypotheses 28: 13-33, 1989.