Large changes in serum free tryptophan levels do not alter brain tryptophan levels: studies in streptozotocin-diabetic rats. 1993

M H Fernstrom, and J D Fernstrom
Department of Psychiatry, University of Pittsburgh School of Medicine, Western Psychiatric Institute and Clinic, PA 15213.

The effect of meal-induced changes in serum free tryptophan (TRP) levels on brain TRP levels was examined in streptozotocin-diabetic rats. Diabetic rats, fasted overnight, were given free access to a non-protein food containing either no fat or large amounts of fat (45% by weight), and were killed 1, 2 or 3 hr thereafter. Ingestion of the high-fat meal produced large increases in both serum non-esterified fatty acid (NEFA; 2-fold) and free TRP levels (2.5-fold), but no increments in cerebral cortical or hypothalamic TRP levels or in the rate of serotonin synthesis in these brain regions. Because the rats were diabetic, serum levels of the other large neutral amino acids (which compete with TRP for transport into brain) did not vary from fasting values in any of the treatment groups. There thus was no uncontrolled variation in the competitive transport of TRP into brain that might have obscured potential effects due to the alterations in serum free TRP levels. The results add further evidence to the notion that TRP transport into the central nervous system is not influenced by the size of the free TRP pool in blood.

UI MeSH Term Description Entries
D007031 Hypothalamus Ventral part of the DIENCEPHALON extending from the region of the OPTIC CHIASM to the caudal border of the MAMMILLARY BODIES and forming the inferior and lateral walls of the THIRD VENTRICLE. Lamina Terminalis,Preoptico-Hypothalamic Area,Area, Preoptico-Hypothalamic,Areas, Preoptico-Hypothalamic,Preoptico Hypothalamic Area,Preoptico-Hypothalamic Areas
D008297 Male Males
D002540 Cerebral Cortex The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulci. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions. Allocortex,Archipallium,Cortex Cerebri,Cortical Plate,Paleocortex,Periallocortex,Allocortices,Archipalliums,Cerebral Cortices,Cortex Cerebrus,Cortex, Cerebral,Cortical Plates,Paleocortices,Periallocortices,Plate, Cortical
D003921 Diabetes Mellitus, Experimental Diabetes mellitus induced experimentally by administration of various diabetogenic agents or by PANCREATECTOMY. Alloxan Diabetes,Streptozocin Diabetes,Streptozotocin Diabetes,Experimental Diabetes Mellitus,Diabete, Streptozocin,Diabetes, Alloxan,Diabetes, Streptozocin,Diabetes, Streptozotocin,Streptozocin Diabete
D004041 Dietary Fats Fats present in food, especially in animal products such as meat, meat products, butter, ghee. They are present in lower amounts in nuts, seeds, and avocados. Fats, Dietary,Dietary Fat,Fat, Dietary
D005230 Fatty Acids, Nonesterified FATTY ACIDS found in the plasma that are complexed with SERUM ALBUMIN for transport. These fatty acids are not in glycerol ester form. Fatty Acids, Free,Free Fatty Acid,Free Fatty Acids,NEFA,Acid, Free Fatty,Acids, Free Fatty,Acids, Nonesterified Fatty,Fatty Acid, Free,Nonesterified Fatty Acids
D000596 Amino Acids Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins. Amino Acid,Acid, Amino,Acids, Amino
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D012701 Serotonin A biochemical messenger and regulator, synthesized from the essential amino acid L-TRYPTOPHAN. In humans it is found primarily in the central nervous system, gastrointestinal tract, and blood platelets. Serotonin mediates several important physiological functions including neurotransmission, gastrointestinal motility, hemostasis, and cardiovascular integrity. Multiple receptor families (RECEPTORS, SEROTONIN) explain the broad physiological actions and distribution of this biochemical mediator. 5-HT,5-Hydroxytryptamine,3-(2-Aminoethyl)-1H-indol-5-ol,Enteramine,Hippophaine,Hydroxytryptamine,5 Hydroxytryptamine
D014364 Tryptophan An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals. Ardeydorm,Ardeytropin,L-Tryptophan,L-Tryptophan-ratiopharm,Levotryptophan,Lyphan,Naturruhe,Optimax,PMS-Tryptophan,Trofan,Tryptacin,Tryptan,Tryptophan Metabolism Alterations,ratio-Tryptophan,L Tryptophan,L Tryptophan ratiopharm,PMS Tryptophan,ratio Tryptophan

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