Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00790 (PGA)
 2,475 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neurotensin (NT) within the stellate ganglion (SG) of the cat is present in axon terminals of extrinsic, presumably preganglionic, neurons and may play a role in ganglionic transmission. NT content of the SG, and of the preganglionic axons which innervate it, was determined by radioimmunoassay in the anesthetized cat under various experimental conditions in order to understand the factors determining the size of the ganglionic NT stores. The immunoreactive NT (iNT) from extracts of SG and its preganglionic inputs (white rami T2 and T3, sympathetic trunk between SG and T4 white ramus) coeluted with synthetic NT(1-13) on RP-HPLC. NT accumulated proximal to ligatures on the preganglionic inputs of the SG. The daily rate of axonal transport of NT, estimated from the accumulation, represents 28.7% of the ganglionic stores of NT. Preganglionic stimulation at 2 Hz for 100 min did not change ganglionic NT content. Preganglionic stimulation at 40 Hz reduced the NT content to 70.4 +/- 1.8% of control in 10 min and to 34.7 +/- 4.2% of control in 20 min. Additional 100 min of 40 Hz stimulation produced no further depletion. The residual iNT, which coeluted with NT1-13, presumably represents a pool of unreleasable NT. Post-depletion recovery was complete in 7 days and showed an initial rapid phase over the first 24 h followed by a slower phase over the remaining 6 days. Pepsin treatment, which has previously been shown to generate iNT from NT precursor in liver and other tissues, provided no evidence of the NT precursor in extracts of SG and its preganglionic input.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Dynamics of neurotensin stores in the stellate ganglion of the cat. 177 41

Treatment of mammalian plasmas with pepsin yielded extraordinary quantities of immunoreactive neurotensin (iNT) and methionine5-enkephalin (iENK). The concentrations measured after pepsin-treatment (iNT, 1-5 microM and iENK, 0.1-0.5 microM) were 1-100 thousand times the normal circulating levels of these peptides. The reactions were shown to be time, temperature and pH dependent and to involve the action of pepsin on albumin-like proteins (Mr, ca, 65,000). Pepsin-generated iNT from rat plasma differed from NT since it reacted only with C-terminal directed antisera and eluted earlier than NT during HPLC on mu-Bondapak C-18. Partially purified iNT was active in two bioassays for NT, one which senses changes in vascular permeability to protein after intradermal injection into rats and another which measures release of histamine from isolated rat mast cells. Other biologic activities generated by pepsin-treating plasma included effects on systemic blood pressure in rats and on the contractility of the isolated guinea pig ileum. Some of these, however, were attributable to the formation of angiotensin- and bradykinin-related peptides. Pepsin-generated iENK gave three major peaks during HPLC, one of which (ca, 25%) co-eluted with oxidized ENK and also registered in a radioreceptor assay for opiate-related substances. In addition, this material produced ENK-like effects on the isolated guinea pig ileum and on vascular permeability in rat skin. The precursor-like protein(s) for iENK were distinguished from adrenal proenkephalins since it did not liberate iENK upon digestion with trypsin and carboxypeptidase B. Since pepsin can mimic renin these results suggest the existence of systems in blood (analogous to the renin/angiotensin system) for the generation of biologically active NT- and ENK-related peptides and they also raise the question as to whether other neuropeptides might be found circulating in precursor form(s).
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PMID:Generation of immunoreactive neurotensin(s) and enkephalin(s) by pepsin-treatment of plasma. 310 14

In a radioassay for Vasoactive Intestinal Peptide (VIP)-binding, eight out of 33 plasma samples from healthy human subjects exhibited specific binding ranging from 2.6% to 46.7% of total [125 I]VIP. This binding was competitively displaced by unlabeled VIP. The structurally homologous peptides, Peptide Histidine Isoleucine (PHI) and secretin, were, respectively, 72-fold and 413-fold less potent than VIP in displacing bound [125 I]VIP, whereas the unrelated peptides, neurotensin, eledoisin, bombesin and metenkephalin, were without effect on the binding. The antibody nature of the VIP-binding factor was suggested by its precipitation with ammonium sulfate, attenuation after absorption with Staphylococcus aureus preparations, precipitation with antisera against human IgG and IgM, and coelution with standard IgG and IgM on anion-exchange and high-performance gel-filtration columns. Pepsin treatment of purified IgG fraction yielded a VIP-binding species with apparent molecular weight of 108 +/- 13 kDa that was precipitated by antiserum against the F(ab)2 fragment of the IgG molecule. These results demonstrate the existence in some human plasmas of an autoantibody that binds VIP.
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PMID:Autoantibody to vasoactive intestinal peptide in human circulation. 383 70