Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C1323099 (sympathomimetic)
 2,957 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In vitro incubation of 24 amino acids with frog liver homogenate shows 4 grades of cholesterogenic values. 1. Alanine, Phenylalanine, Tyrosine and DOPA give positive results. Other amino acids were able to sustain the original amounts of cholesterol to different proportions e.g. 2. Aspartic acid, Proline and Valine (50%). 3. Sodium Acetate, Arginine, Cysteine, Leucine, Norleucine, Methionine and Serine (more than 50%). 4. Aminobutyric, Glutamic, Glycine, Histidine, Hydroxyproline, Isoleucine, Lysine, Ornithine, Threonine and Tryptophan (less than 50% to negligible). DOPA gives the maximum yield of 73.1% It also shows high cholesterogenic values in different organs both in vitro and in vivo. It is thus a major precursor of cholesterol in animal tissues. Scheme of biosynthesis of cholesterol from DOPA ARE GIVEN ON THE BASIS OF KNOWN FACTS. A postulated scheme of direct synthesis of sterid molecule from DOPA is also provided. DOPA also showns sympathomimetic effects upon subcutaneous administration and blood cholesterol is reduced to more than 50%. Although there are numerous publications detailing the various aspects of biosynthesis of cholesterol and hyper and hypo-cholesterolemia yet the exact realtionship between the amino acids and cholesterol synthesis is not properly understood. Recent publications of Shrivastava (1975 a,b,c) have aspecially drawn attention to the high cholesterogenic effects of 3:4-dihydroxyphenylalanine. This work presents evidence that DOPA is infact a major and potential source of cholesterol not only in liver but in other animal tissues as well.
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PMID:3:4-Dihydroxyphenzylalanine and biosynthesis of cholesterol in vivo and in vitro experimental studies. 82 10

The effects of pindolol on the prolactin (PRL) and growth hormone (GH) responses to intravenous tryptophan (LTP) were studied in eight healthy male volunteers. Pindolol pretreatment (40 mg over 48 h) markedly attenuated the GH response to LTP and modestly, but significantly, reduced the LTP-induced increase in plasma PRL. The disposition of LTP following infusion was not altered by pindolol. While the data are consistent with 5-HT1A receptor mediation of PRL and GH responses to LTP, the intrinsic sympathomimetic actions of pindolol might also be involved in the attenuation of the endocrine responses to LTP.
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PMID:Pindolol decreases prolactin and growth hormone responses to intravenous L-tryptophan. 200 40

Kynuramine, an endogenous metabolite of L-tryptophan, was found to function as an indirectly acting sympathomimetic amine in rat atria in vitro. Kynuramine released tritium from atria preloaded with [3H]norepinephrine (NE), an effect which was blocked completely by pretreatment with reserpine or 6-hydroxydopamine. Release by kynuramine was calcium-independent and was potentiated by inhibition of monoamine oxidase but was only partially sensitive (50%) to inhibition by cocaine (10(-4)M). The ability of kynuramine to enter cardiac cells was demonstrated in whole atria by measuring its intracellular deamination rate by monoamine oxidase. Blockade of neuronal uptake (cocaine) and extraneuronal uptake (SKF 550) had no effect upon this measure. It is concluded that knyuramine releases cardiac NE, in part, by a cocaine-sensitive mechanism but that the process operating for the membrane transport of kynuramine in both neuronal and non-neuronal cells remains uncertain. The data are discussed in relation to the possible cardiac consequences of L-tryptophan ingestion in man.
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PMID:Cardiac norepinephrine releasing action of kynuramine, an endogenous diamine derived from L-tryptophan. 650 15