Tryptophan is an essential amino acid, precursorof serotonin. Serotonin (5HT) regulates the secretion ofpituitary growth hormone (GH), which in turn stimulatesthe liver to produce insulin-like growth factor-I (IGF-I) thatis necessary for development and growth. The aim of ourstudy was to investigate the effects of an excess of tryptophanin the diet of pregnant rats on the differentiation ofskeletal muscle tissue.Methods We conducted an immunohistochemical studyon the IGF-I expression in hepatic and muscle tissues inoffspring, and then, we associated this molecular data withmorphological effects on the structure of the muscle fibersand hepatic tissue at different postnatal weeks, from birthto sexual maturity. Measurements of 5HT, GH in blood,and of tryptophan hydroxylase (Tph) activity in gastrointestinaltracts tissue were also taken.Results Hyperserotonemia and higher values of Tphactivity were detected in both pregnant rats and pups. Verylow 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 werefound.Conclusions Our data suggest that an excess of tryptophanin the diet causes hyperserotonemia in fetus. Hyperserotonemiaresults in an excess of serotonin in the brainwhere it has an adverse effect on the development ofserotonergic neurons. The affected neurons do not regulateoptimally the secretion of pituitary GH that consequentlydecreases. This limits stimulation in the liver to produceIGF-I, crucial for development and growth of pups.
Effects of high-tryptophan diet on pre- and postnatal development in rats: a morphological study
Castrogiovanni PPrimo
;MUSUMECI, GIUSEPPE
Secondo
;MAGRO, Gaetano Giuseppe;IMBESI, RosaUltimo
2014-01-01
Abstract
Tryptophan is an essential amino acid, precursorof serotonin. Serotonin (5HT) regulates the secretion ofpituitary growth hormone (GH), which in turn stimulatesthe liver to produce insulin-like growth factor-I (IGF-I) thatis necessary for development and growth. The aim of ourstudy was to investigate the effects of an excess of tryptophanin the diet of pregnant rats on the differentiation ofskeletal muscle tissue.Methods We conducted an immunohistochemical studyon the IGF-I expression in hepatic and muscle tissues inoffspring, and then, we associated this molecular data withmorphological effects on the structure of the muscle fibersand hepatic tissue at different postnatal weeks, from birthto sexual maturity. Measurements of 5HT, GH in blood,and of tryptophan hydroxylase (Tph) activity in gastrointestinaltracts tissue were also taken.Results Hyperserotonemia and higher values of Tphactivity were detected in both pregnant rats and pups. Verylow 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 werefound.Conclusions Our data suggest that an excess of tryptophanin the diet causes hyperserotonemia in fetus. Hyperserotonemiaresults in an excess of serotonin in the brainwhere it has an adverse effect on the development ofserotonergic neurons. The affected neurons do not regulateoptimally the secretion of pituitary GH that consequentlydecreases. This limits stimulation in the liver to produceIGF-I, crucial for development and growth of pups.File | Dimensione | Formato | |
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