Rat brain serotonin synthesis under prolonged consumption of fructose solution

Abstract

Key metabolites and enzymes of rat brain serotonin biosynthesis pathway under the development of obesity induced by the consumption of 10% fructose solution, have been studied. A reduction of tryptophan by 60±10 % (p < 0.05, n = 10), 5-hydroxytryptophan, a direct precursor of serotonin biosynthesis, and by 52±15 % (p < 0.05, n = 10) and serotonin by 45±18 % (p < 0.05, n = 10), respectively, has been found. A reduction in the activity of serotonin biosynthetic pathway key speed limiting enzyme –tryptophan hydroxylase by 30±2 % (p < 0.05, n = 10), and reduction of tryptophan decarboxylase activity by 58±10 % (p < 0.05, n = 10) in the brain of rats of experimental group has been found. The increase of monoamine oxidase activity in the rat brain after 10-week consumption of 10% fructose solution by 62±27 % (p < 0.05, n = 10) has been discovered. These results testify a violation of the biosynthesis of serotonin in the development of fructose-induced obesity, and indicate possible involvement of serotoninergic neurotransmitter system of brain in the development and progression of this multifactorial disease.

Keywords

• serotonin
• tryptophan
• tryptophan hydroxylase
• monoamine oxidase
• obesity
• fructose