Hormones serotonin

Some prominent 3-substituted derivatives include skatole (3-methylin-dole), which has a faecal odour, and indoIyl-3-acetic acid (sold as a plant rooting powder). Many indoles are biologically important for example, tryptamine is the precursor of two hormones serotonin, a vasoconstrictor, and melatonin, which is involved in the control of circadian rhythm. In addition, the amino acid tryptophan is an essential component of proteins (see Box 7.1). 

Parthenolide, a constituent of feverfew, inhibits the release of certain chemicals, including the hormone serotonin, which is produced during a migraine attack, and certain inflammatory mediators, including the hormone prostaglandin, which regulates inflammation. Feverfew is used for prevention of migraines and headaches (see Chapter 30). 

The amphetamine analogue fenfluramine, whose synthesis you designed while you were reading Chapter 31, used to be marketed as an anorectic (appetite-suppressant)—it stimulates the production of the hormone serotonin and makes the body feel satisfied—until it became clear that some undesirable side-effects could be avoided by administering it solely as the (S)-enantiomer. Fenfluramine relaunched as the enantiomerically pure dexfenfluramine, and was reputedly a turning point for your overweight patients —was available in the USA as a component of the slimming pill Redux. 

Rarely they may also express ectopic hormones (calcitonin, adrenocortical hormone, beta melanocyte stimulating hormone, serotonin, parathyroid hormone). A metastasis from a pulmonary SCNEC should always be considered in the differential diagnosis. 

The hormones serotonin and melatonin are biosynthesized from tryptophan by a series of reactions, including one that involves an NIH shift. 

Cells which stain with silver salts and which are found in several sites in the alimentary tract. They synthesize the hormone serotonin. 

This is a tumour of argentaffin cells (cells which stain with silver salts), usually sited in the ileum or appendix, or less commonly in the bronchus, pancreas or stomach. These cells normally synthesize the hormone serotonin (5-hydroxytryptamine) which is a powerful smooth-muscle stimulant and vasoconstrictor. In carcinoid syndrome this hormone is secreted in excess amounts. The clinical symptoms of this condition include flushing, diarrhoea and bronchospasm. Carcinoid syndrome can be diagnosed biochemically by detection of the serotonin metabolite, 5-hydroxyindoleacetic acid, in excess amounts in the urine. 

A metabolite of the hormone, serotonin (5-hydroxytryptamine). It is excreted in excess amounts in the urine of patients with carcinoid syndrome, a condition in which there is excessive synthesis of serotonin. 

Tryptophan is also required for the synthesis of the hormones serotonin and melatonin. 

Also called adrenaline a hormone secreted by the adrenal gland that prepares the organism for "flight or fight.") (A hormone synthesized in the pineal gland. Certain mental disorders are believed to be related to serotonin levels in the brain.)... 

Certain amino acids and their derivatives, although not found in proteins, nonetheless are biochemically important. A few of the more notable examples are shown in Figure 4.5. y-Aminobutyric acid, or GABA, is produced by the decarboxylation of glutamic acid and is a potent neurotransmitter. Histamine, which is synthesized by decarboxylation of histidine, and serotonin, which is derived from tryptophan, similarly function as neurotransmitters and regulators. /3-Alanine is found in nature in the peptides carnosine and anserine and is a component of pantothenic acid (a vitamin), which is a part of coenzyme A. Epinephrine (also known as adrenaline), derived from tyrosine, is an important hormone. Penicillamine is a constituent of the penicillin antibiotics. Ornithine, betaine, homocysteine, and homoserine are important metabolic intermediates. Citrulline is the immediate precursor of arginine. 

Important products derived from amino acids include heme, purines, pyrimidines, hormones, neurotransmitters, and biologically active peptides. In addition, many proteins contain amino acids that have been modified for a specific function such as binding calcium or as intermediates that serve to stabilize proteins—generally structural proteins—by subsequent covalent cross-hnk-ing. The amino acid residues in those proteins serve as precursors for these modified residues. Small peptides or peptide-like molecules not synthesized on ribosomes fulfill specific functions in cells. Histamine plays a central role in many allergic reactions. Neurotransmitters derived from amino acids include y-aminobutyrate, 5-hydroxytryptamine (serotonin), dopamine, norepinephrine, and epinephrine. Many drugs used to treat neurologic and psychiatric conditions affect the metabolism of these neurotransmitters. 

A number of non-hormonal therapies have been studied for symptomatic management of vasomotor symptoms, including antidepressants [e.g., selective serotonin reuptake inhibitors (SSRIs) and venlafaxine], herbal products (e.g., soy, black cohosh, and dong quai), and a group of miscellaneous agents (e.g., gabapentin, clonidine, and megestrol). The choice of therapy depends on the patient s concomitant disease states, such as depression and hypertension, and the risk for potential adverse effects. 

SSRIs are theorized to reduce the frequency of hot flashes by increasing serotonin in the central nervous system and by decreasing LH. Of the SSRIs, citalopram, paroxetine, and sertraline all have been studied and have demonstrated a reduction in hot flashes while treating other symptomatic complaints such as depression and anxiety.33 Venlafaxine, which blocks the reuptake of serotonin and norepinephrine, has demonstrated a reduction in hot flashes primarily in the oncology population.34 Overall, these antidepressant medications offer a reasonable option for women who are unwilling or cannot take hormonal therapies, particularly those who suffer from depression or anxiety. These agents should be prescribed at the lowest effective dose to treat symptoms and may be titrated based on individual response. 

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