Dietary docosahexaenoic acid-enriched phospholipids normalize urinary melatonin excretion in adult (n-3) polyunsaturated fatty acid-deficient rats

J Nutr. 1999 Nov;129(11):2074-80. doi: 10.1093/jn/129.11.2074.

Abstract

Melatonin (MEL) plays an essential role in physiologic functions associated with darkness. We examined the effects of docosahexaenoic acid (DHA)-enriched phospholipids from pig brains (BPL) or hen eggs (EPL), as sources of DHA, on lipid FA composition of pineal membranes and daytime and nighttime concentrations of 6-sulfatoxymelatonin (aMT6) in adult male control and (n-3)-deficient rats fed BPL and EPL diets for 5 wk. In two experiments, at 3 wk of age, rats were divided into subgroups and fed semipurified diets containing either peanut oil [(n-3)-deficient group] or peanut plus rapeseed oil (control group) and two dietary formulas containing either 3.5 g/100 g diet of BPL (Experiment 1) or 5.0 g/100 g diet of EPL (Experiment 2). BPL and EPL diets provided approximately 200 mg of DHA/100 g diet. During the daytime, aMT6 concentrations were not significantly different among groups. Conversely, the (n-3)-deficient rats had significantly lower nighttime aMT6 concentrations than the control rats. BPL and EPL did not affect urinary nighttime aMT6 concentration in the control group, whereas (n-3)-deficient + BPL or EPL groups exhibited significantly higher nighttime aMT6 concentrations than the (n-3)-deficient group (76 and 110%, respectively). The level of DHA was significantly higher in the pineal glands of control rats than in (n-3)-deficient rats. In rats fed EPL and BPL, the level of DHA reached a plateau, between 10 and 11 mg/100 mg total fatty acids in control + BPL or EPL and (n-3)-deficient + BPL or EPL groups. These findings suggest that new DHA-enriched formulas may be used as an efficient alternative source of (n-3) polyunsaturated fatty acids to normalize MEL secretion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chickens
  • Circadian Rhythm
  • Dietary Fats / administration & dosage
  • Docosahexaenoic Acids / administration & dosage*
  • Docosahexaenoic Acids / pharmacology
  • Fatty Acids / analysis*
  • Fatty Acids, Omega-3 / administration & dosage*
  • Male
  • Melatonin / analogs & derivatives*
  • Melatonin / urine
  • Phospholipids / administration & dosage*
  • Phospholipids / metabolism
  • Pineal Gland / chemistry*
  • Pineal Gland / drug effects
  • Pineal Gland / metabolism
  • Rats
  • Swine

Substances

  • Dietary Fats
  • Fatty Acids
  • Fatty Acids, Omega-3
  • Phospholipids
  • 6-sulfatoxymelatonin
  • Docosahexaenoic Acids
  • Melatonin