Related Experiment Video
Updated: May 7, 2026
Rapid In Situ Hybridization using Oligonucleotide Probes on Paraformaldehyde-prefixed Brain of Rats with Serotonin Syndrome
Published on: September 23, 2015
Serotonin (5HT) expression in rat pups treated with high-tryptophan diet during fetal and early postnatal development
Giuseppe Musumeci1, Carla Loreto1, Francesca Maria Trovato2
1Department of Bio-Medical Sciences, Human Anatomy and Histology Division, University of Catania, Italy.
Insights
A high-tryptophan diet in pregnant rats led to hyperserotonemia (excess serotonin) in pups, significantly reducing growth hormone levels and impairing skeletal muscle development. This highlights potential risks of maternal diet on fetal development.
Area of Science:
- Neuroscience
- Developmental Biology
- Nutritional Science
Background:
- Serotonin (5HT) is a crucial neurotransmitter regulating brain development and growth hormone secretion.
- Tryptophan (Trp), the serotonin precursor, is an essential amino acid obtained solely through diet.
- Maternal diet composition can influence fetal development and neuroendocrine functions.
Purpose of the Study:
- To investigate the impact of a high-tryptophan diet during pregnancy on rat pup growth, survival, and physiological parameters.
- To determine the effects of maternal tryptophan supplementation on fetal serotonin and growth hormone levels.
- To assess the consequences of altered serotonin levels on skeletal muscle morphology in offspring.
Main Methods:
- Pregnant rats were fed a high-tryptophan diet; pups were monitored for growth and survival.
- Blood samples from pups were analyzed for serotonin and growth hormone levels using ELISA.
- Gastric serotonin expression was evaluated via immunohistochemistry and Western blot.
- Skeletal muscle tissue morphology was examined using histological analysis.
Main Results:
- Pups from dams on a high-tryptophan diet exhibited hyperserotonemia and significantly lower growth hormone levels compared to controls.
- Increased serotonin expression was confirmed in the gastric tissue of experimental pups.
- Histological examination revealed deleterious alterations and underdeveloped skeletal muscle fibers in experimental pups.
- High-tryptophan diet induced hyperserotonemia, negatively impacting fetal development and growth hormone production.
Conclusions:
- Maternal high-tryptophan intake during gestation induces fetal hyperserotonemia.
- Fetal hyperserotonemia adversely affects the development of serotonergic neurons and growth hormone production.
- These disruptions lead to impaired skeletal muscle development and potentially compromised growth in offspring.
Abstract:
Serotonin (5HT) is a neurotransmitter synthesized in serotonergic neurons of the central nervous system and in the enterochromaffin cells of the gastrointestinal tract. 5HT regulates growth and maturation of some cerebral regions in the developing brain as well as the secretion of pituitary growth hormone. This hormone is necessary for development and growth through the stimulation of insulin-like growth factor synthesis. The precursor of 5HT, tryptophan (Trp), is an essential amino acid, since the human organism is unable to synthesize it and it is assumed only through diet. The aim of our study was to analyze how a high-tryptophan diet in pregnant rats affects growth and survival of pups until weaning. We monitored the number and weight of pups until weaning. Then, we detected serotonin and growth hormone levels in whole blood by ELISA of surviving pups at the end of the lactation period. We also analyzed by means of immunohistochemistry and Western blot the expression of serotonin in rat gastric tissue and the morphological structure of skeletal muscle tissue of both control and experimental pups. Hyperserotonemia and very low levels of growth hormone were detected in experimental pups compared to controls. Immunohistochemistry demonstrated a strong serotonin expression in stomach samples confirming that a high intake of tryptophan increases the production of serotonin in enterochromaffin cells, thereby resulting in hyperserotonemia in pups. These data were also strengthened by Western blot analysis. Histological alterations of skeletal muscle fibers in experimental pups were found and showed that in experimental samples the muscle tissue demonstrated deleterious alterations, being less developed and defined. Our data suggest that a high-tryptophan diet in pregnant rats induces hyperserotonemia in the fetus. Hyperserotonemia results in an excess of serotonin in the brain where it has a negative influence on development of serotonergic neurons and consequently on growth hormone production.
