Serum serotonin

Hyperserotonemia has been a consistent finding in subjects with autism, which may be due to activity of serotonin-associated platelet proteins (Hranilovic et al., 2008, 2009). Interestingly, 99% of blood serotonin is contained in platelets (Anderson et al., 1987) and studies have shown that there is an approximate 50% increase in blood-levels of serotonin in subjects with autism vs. controls (McBride et al., 1998). Hypotheses for increased serotonin include increased synthesis of serotonin by tryptophan hydroxylase (TPHl), increased uptake of serotonin into platelets via serotonin transporters (5-HTT), diminished release of serotonin from platelets via serotonin 2A receptor, and decreased breakdown of serotonin by monoamine oxidase (MAOA) (Hranilovic et al., 2008). A study by Hranilovic et al. (2008) identified polymorphisms of tryptophan hydroxylase and MAOA with increased serum serotonin levels. Similarly, haplotype analysis has shown a significant association between polymorphisms of TPHl and increased serotonin in whole blood (Cross et al., 2008). 

An idea which has been advanced in a recent discussion 16, 17) is that Cp is a stress enzyme of the circulation, possibly controlling levels of serum serotonin, epinephrine, melatonin, and other biogenic amines which are substrates for this enzyme. 

Rosenberg, J. C., Davis, R., Moran, W. H. and Zimmermann, B., Serum serotonin concentration and urinary 5-hydroxyindole acetic acid excretion following intestinal obstruction and resection. Fed. Proc. 18, 503 (1959). 

Fig. 34.2. FDOPA-PET (k MIP),CT (middle selected coronal slice), and Ga-DOTA-TATE PET (right MIP) of a patient with liver and lymph node metastases of a well-differentiated NET with negative im-munohistochemical detection of serotonin and normal serum serotonin levels, showing no increased uptake of metastases on FDOPA-PET but highly increased uptake on DOTA-TATE-PET...

Separation methods, multichromato-graphic la 56 Serine la 246,356 lb 132 Serotonin la 70,76,239,240,262,355, 380 lb 37-39,231,243,348 Serotonin metabolites lb 327 Serum lipids la 89 Serum proteins la 74 Sesquiterpene derivatives lb 239,446 Sesquiterpene esters lb 239 Sesquiterpene glucosides la 327 Sesquiterpene lactones lb 448 Sevin lb 387-389 Si 50 000, specific surface area la 91 Silica gel, caffeine-impregnated la 85 -, surface modified la 3 Silica gel 60, specific surface area la 91... 

There is a recent clinical report by Emil Coeearo and colleagues that I think might be relevant to the kind of thing you have done in rats. They have been looking at endocrine responses to fenfluramine in humans as a marker of central serotonergic function. And they have observed an increase in serum prolactin concentration, which is felt to be due to serotonin release. They reported that, in subjects who received a seeond dose of fenfluramine within 12 days after the first dose, that there was a blunted response to serum prolactin. 

Patients sustain convulsions and neurological deterioration. The urine contains low levels of the metabolites of serotonin, norepinephrine and dopamine. The reductase also plays a role in the maintenance of tetrahydrofolate levels in brain, and some patients have had low folate levels in the serum and CNS. Treatment has been attempted with tryptophan and carbidopa to improve serotonin homeostasis and with folinic acid to replete diminished stores of reduced folic acid. This therapy is sometimes effective. Diagnosis involves assay of DHPR in skin fibroblasts or amniotic cells. Phenylalanine hydroxylase activity is normal. 

See also research, medical biochemical individuality and, 206-207 metabolism, 203 variations, exceptions and, 202 vision, 202-203 vitamin research and, 204-205 scopolamine, 228 scurvy, 167-168 self-esteem, genetics and, 16 self-selection of foods, 180 Selye, Hans, 230 senile dementia, 34-35, 227, 230 sensory physiology and psychology, 205 serotonin, 236 serum amylase, 80-81 serum lipase, 81 serum phenol sulfatase, 81 sex behavior, 100, 104-105 psychiatry and, 231 sex differences... 

Tournel G, Houdret N, Hedouin V, Deveaux M, Gosset D, Lhermitte M. 2001. High-performance liquid chromatographic method to screen and quantitate seven selective serotonin reuptake inhibitors in human serum. J Chromatogr B Biomed Sci Appl 761(2) 147-158. 

Methods and devices for transdermal delivery of lithium (US6,375,990 Bl) Methods to estimate serotonin and norepinephrine transporter occupancy after drug treatment using patient or animal serum (provisional filing April 2001)... 

Statins should be avoided in active liver disease and unexplained raised serum transaminases. Some antihistamines, such as diphenhydramine and promethazine, should be used with caution in mild-to-moderate liver disease. Selective serotonin re-uptake inhibitors should be used at a reduced dose or avoided in hepatic impairment. 

Salbutamol, 280 Salsalate, 90 Sapiens, homo, 316 Semustine, 12, 15 Serotonin, 96, 343 Serum cholesterol, 56, 78, 161... 

The regulation of calcitonin synthesis and release from the parafollicular C cells of the thyroid gland is calcium dependent. Rising serum calcium is the principal stimulus responsible for calcitonin synthesis and release. Other hormones, such as glucagon, gastrin, and serotonin, also stimulate calcitonin release. Calcitonin has been isolated in tissues other than the parafollicular C cells (parathyroid, pancreas, thymus, adrenal), but it is not known whether this material is biologically active. 

Lithium has numerous pharmacologic effects. It is able to cross through sodium channels, competing with monovalent and divalent cations in cell membranes (AHFS, 2000). Animal studies have shown that lithium at a serum level of 0.66 + — 0.08 mEq/L can increase the amphetamine-induced release of serotonin (5-hydroxytryptamine [5-HT]) and the concentrations of a serotonin metabolite (e.g., 5-hydroxyindoleacetic acid [5-HIAA]) in the perifornical hypothalamus (PFH) of rats before and after chronic lithium chloride administration (Baptista et ah, 1990), a mechanism possibly involved in lithium s antidepressant effect. The precise neurobiological mechanisms through which lithium reduces acute mania and protects against recurrence of illness remain uncertain (Lenox and Hahn,... 

Serotonin—An organic compound formed from tryptophan and found in animal and human tissue, especially the brain, blood serum, and gastric mucous membranes, and active in vasoconstriction, stimulation of the smooth muscles, transmission of impulses between nerve cells, and regulation of cyclic body processes. 

Bjerkenstedt L, Flyckt L, Overo KF, et al. Relationship between clinical effects, serum drug concentration and serotonin uptake inhibition in depressed patients treated with citalopram. EurJ Clin Pharmacol 1985 28 553-557. 

Before the identification of 5-hydroxytryptamine (5-HT), it was known that when blood is allowed to clot, a vasoconstrictor (tonic) substance is released from the clot into the serum. This substance was called serotonin. Independent studies established the existence of a smooth muscle stimulant in intestinal mucosa. This was called enteramine. The synthesis of 5-hydroxytryptamine in 1951 permitted the identification of serotonin and enteramine as the same metabolite of 5-hydroxytryptophan. 

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