Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of 8-N-N-diethylamino octyl 3,4,5-trimethoxybenzoate (TMB-8) and trifluoperazine (TFP) on the early phase (10 min) of the release of pancreatic hormones from isolated rat islets were investigated. TMB-8 and TFP stimulated insulin, glucagon, and somatostatin release in a dose-dependent manner at a low glucose concentration (2.5 mM). The levels of glucagon and somatostatin release were also stimulated by these two agents at a high glucose concentration (10 mM). Their effects were independent of external calcium ion level. These two agents did not modify insulin release at the high glucose concentration. The stimulative effects of the two agents on the release of these hormones were partially suppressed when the islets were pretreated with 6-hydroxydopamine (6-OHDA), a chemical adrenergic denervator that acts at nerve endings. In this situation, the norepinephrine (NE) released from pancreatic islets decreased to 44% of that of non-treated islets (P less than 0.01). The addition of NE (10(-9) M) to the incubation medium increased insulin, glucagon, and somatostatin secretion by 20-30% over control levels (P less than 0.05). In conclusion, the early phase of pancreatic hormone release was stimulated by TMB-8 and TFP. Our results strongly suggest that these two drugs could be mediated by the NE released from nerve endings in the islets.
 ...
PMID:Stimulative effects of TMB-8 and trifluoperazine on pancreatic hormone release. 256 59

We have examined the factors regulating the mucosal release of somatostatin-like immuno-reactivity (SRIF-LI) from 1-cm2 sheets of isolated canine gastric antral mucosa mounted in a Ussing chamber. SRIF-LI was released predominantly into the luminal perfusate, was maximal at pH 2.5, 1,987 +/- 319 pg X ml-1 X h-1, and reached a nadir at pH 6.0 of 89 +/- 24 pg X ml-1 X h-1. Increasing extracellular Ca2+ to 10 mM stimulated the release of SRIF-LI at both high and low pH. The Ca2+ ionophore A23187 had no apparent effect at either pH 2.5 or 7.0. LaCl3 stimulated the release of SRIF-LI at pH 7.0 but not at pH 2.5. Ouabain and TMB-8 had no significant effect on the release of SRIF-LI. At pH 7.0, trifluoperazine (TFP) stimulated release of SRIF-LI (80 +/- 10 pg X ml-1 X h-1). EGTA stimulated release of SRIF-LI at pH 2.5 (1,134 +/- 137 pg X ml-1 X h-1) and at pH 7.0 (300 +/- 57 pg X ml-1 X h-1), which was reversed by replacement of Ca2+ (22 +/- 6 pg X ml-1 X h-1). Thus Ca2+ appears to exert a dual effect on the release of SRIF-LI: both an increase and depletion of extracellular Ca2+ release SRIF-LI.
 ...
PMID:A dual role of calcium in release of somatostatin from canine gastric antral mucosa. 614 72

In experimental models and in humans, somatostatin (SRIF) is able to contract certain vascular structures. The present experiments were designed to assess the capacity of SRIF to contract cultured rat aortic vascular smooth muscle cells (VSMC), and to analyze the possible mechanisms involved. Cells incubated with SRIF showed a significant reduction in planar cell surface area, in a time- and dose-dependent manner. This effect was partially blocked by preincubating the cells with a combination of calcium antagonists (10 microM verapamil, plus 10 microM 3,4,5-Trimethoxybenzoic acid 3-(diethylanino) octyl ester TMB)-8). SRIF was also able to stimulate myosin light-chain phosphorylation in VSMC. A small but significant increase of intracellular calcium concentration, and decreased levels of cAMP, without changes in cGMP, were detected in VSMC incubated with SRIF. A search for the known SRIF receptors present in these cells, by reverse transcription-polymerase chain reaction, only SRIF receptor-4 was found to be present. These results demonstrate the ability of SRIF to contract cultured rat VSMC. The contraction observed in these cells appears to be due to a mixed mechanism, that involves [Ca2+]i and cAMP as second messengers, and is likely mediated via SRIF receptor-4.
 ...
PMID:Mechanisms involved in the somatostatin-induced contraction of vascular smooth muscle cells. 1050 70

A general scheme for the efficient synthesis of Trp-containing cystine peptide by the successive treatment with methyltrichlorosilane-diphenylsulfoxide in trifluoroacetic acid (TFA) and trifluoromethanesulfonic acid (TFMSA)-thioanisole in TFA, is described. A disulfide bond-forming reaction by silyl chloride-sulfoxide system is completed within 10-15 min without modifications at sensitive residues (Tyr, His, Met) in peptide chain, except for a Trp residue. In order to synthesize a Trp-containing cystine peptide using silyl chloride, the indole moiety of Trp has to be protected since the chlorination of the indole ring proceeded predominantly. A formyl group has been the only protecting group employed for this purpose in practical syntheses of cystine peptides, although it was clarified that a side reaction derived from the formyl group migration was inevitable in the synthesis of somatostatin. Firstly, we examined the application of the following Nin-protecting groups, mesitylene-2-sulfonyl (Mts), cyclohexyloxycarbonyl (Hoc), and 2,4-dimethylpent-3-yloxycarbonyl(Doc) for an efficient synthesis of the Trp-containing cystide peptide by the silyl chloride method. In order to find a feasible scheme of the successive treatment with CH3SiCl3-PhS(O)Ph/TFA and TFMSA-thianisole in TFA, we synthesized somatostatin using Trp(Mts), Trp(Hoc) or Trp(Doc) derivative. The Doc group was found to be the most suitable as an indole protecting group, since the protecting group was cleaved under mild conditions (4 degrees C, 30 min) via the corresponding Nin-carboxylic acid intermediate. We then applied the above procedure to the synthesis of endothelin-1 (ET-1), a peptide containing 21-amino acid residues having a C-terminal Trp residue and two disulfide bonds, by regioselective disulfide formation. The combination of the silyl chloride method with iodine oxidation using S-acetamidomethyl (Acm) and S-tBu groups for the regioselective double disulfide formation was successfully applied to give a highly purified ET-1. These results also show that the Nin-Doc group would be useful for the efficient syntheses of complex cystine-peptides by the silyl chloride method.
 ...
PMID:[A novel synthetic approach of tryptophan-containing cystine peptides by regioselective disulfide bond-forming reaction using the silyl chloride-sulfoxide system]. 1068 66