title: Effects of high-tryptophan diet on pre- and postnatal development in rats: a morphological study.
abstract: OBJECTIVE
  Tryptophan is an essential amino acid, precursor of serotonin. Serotonin (5HT) regulates the secretion of pituitary growth hormone (GH), which in turn stimulates the liver to produce insulin-like growth factor-I (IGF-I) that is necessary for development and growth. The aim of our study was to investigate the effects of an excess of tryptophan in the diet of pregnant rats on the differentiation of skeletal muscle tissue.
  
  
  METHODS
  We conducted an immunohistochemical study on the IGF-I expression in hepatic and muscle tissues in offspring, and then, we associated this molecular data with morphological effects on the structure of the muscle fibers and hepatic tissue at different postnatal weeks, from birth to sexual maturity. Measurements of 5HT, GH in blood, and of tryptophan hydroxylase (Tph) activity in gastrointestinal tracts tissue were also taken.
  
  
  RESULTS
  Hyperserotonemia and higher values of Tph activity were detected in both pregnant rats and pups. Very low levels of GH were detected in experimental pups. Morphological alterations of the muscle fibers and lower IGF-I expression in hepatic and muscle tissue in pups were found.
  
  
  CONCLUSIONS
  Our data suggest that an excess of tryptophan in the diet causes hyperserotonemia in fetus. Hyperserotonemia results in an excess of serotonin in the brain where it has an adverse effect on the development of serotonergic neurons. The affected neurons do not regulate optimally the secretion of pituitary GH that consequently decreases. This limits stimulation in the liver to produce IGF-I, crucial for development and growth of pups.
authors: Department of Bio-Medical Science, Section of Human Anatomy and Histology, University of Catania, Via S. Sofia 87, 95123, Catania, Italy.
authors: Paola
authors: P
authors: Castrogiovanni
authors: Giuseppe
authors: G
authors: Musumeci
authors: Francesca Maria
authors: FM
authors: Trovato
authors: Rosanna
authors: R
authors: Avola
authors: Gaetano
authors: G
authors: Magro
authors: Rosa
authors: R
authors: Imbesi
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation / Q000187:drug effects; D005260:Female; D005333:Fetus / Q000187:drug effects / Q000378:metabolism; D041981:Gastrointestinal Tract / Q000187:drug effects / Q000378:metabolism; D013006:Growth Hormone / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000097:blood; D014364:Tryptophan / Q000008:administration & dosage*; D014365:Tryptophan Hydroxylase / Q000378:metabolism
chemical_list: C548904:insulin-like growth factor-1, rat; D012701:Serotonin; D007334:Insulin-Like Growth Factor I; D014364:Tryptophan; D013006:Growth Hormone; D014365:Tryptophan Hydroxylase
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