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

Cells prepared from frog esophageal peptic glands by dispersal in low-Ca2+ medium (peptic acini) or 1 mM ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA)-containing medium ("EGTA cells") were compared. EGTA cells were characterized by decreased secretory responses to agonists [bombesin (BB), acetylcholine, and isoproterenol] and intracellular messenger activators (forskolin, 12-O-tetradecanoyl-phorbol-13-acetate), decreased relative intrinsic efficacies of muscarinic agonists, and somatostatin insensitivity. Decreased BB and muscarinic receptor responses were not associated with changes in receptor number or characteristics. The time course of BB- and acetylcholine-stimulated pepsinogen secretion indicated that the marked reduction was confined largely to the late secretory phase (2-30 min), dependent on extracellular Ca2+, rather than early phase (less than 2 min) secretion, which is related to release of intracellular Ca2+. The defect could be reversed by the Ca2+ ionophore A23187. BB-stimulated intracellular Ca2+ mobilization measured with fura-2/AM was similar in the two cell preparations, whereas BB-stimulated 45Ca2+ uptake was reduced threefold in EGTA cells, and this defect was also reversed by A23187. Somatostatin inhibited both BB-stimulated secretion and 45Ca uptake by peptic acini, but it had no significant effect on these parameters in EGTA cells. Cytochalasin B inhibited BB stimulation in peptic acini but not EGTA cells. These findings suggest that peptic cells isolated with EGTA exhibit decreased secretory responses that are due at least in part to impairment of a mechanism for uptake of extracellular Ca2+.
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PMID:Decreased secretion due to a Ca2+ influx defect in frog peptic cells isolated with EGTA. 215 19

We studied the release of insulin, glucagon, and somatostatin in response to glucose, glyceraldehyde (GA), and alpha-ketoisocaproate (KIC) from rat kidneys containing transplanted insulinomas. Kidneys were perfused about 11 wk after transplantation when the plasma glucose concentration of the fed animals had decreased from 180 +/- 7 to 95.1 +/- 9.9 mg/dl and plasma insulin concentrations had increased from 2.6 +/- 0.5 to 14.2 +/- 2.0 ng/ml. The insulin content of the tumor-containing kidney ranged from 40 to 679 micrograms; the glucagon and somatostatin concentrations ranged from undetectable levels to 3.7 micrograms and 248 ng, respectively. The average response to 30 mM glucose and 10 mM GA was a four- to fivefold increase in insulin secretion, whereas 30 mM KIC caused a 16- to 28-fold increase. In vitro stimulation of the insulinoma with 30 mM glucose primed the beta-cell response to a second stimulus following a short rest period. Cytochalasin B did not enhance this primed glucose response. Diazoxide inhibited glucose, GA, and KIC-stimulated insulin release. Glucose, GA, and KIC stimulated glucagon release in 2 of 17 insulinomas studied here. Somatostatin release was not seen in any of the experiments. These findings show that this islet cell tumor transplanted under the kidney capsule releases insulin in response to physiologic and model fuel substances. Thus, this particular transplantable tumor offers an opportunity to study the biochemistry and biophysics that underlie fuel-stimulated insulin release.
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PMID:Fuel-induced insulin release in vitro from insulinomas transplanted into the rat kidney. 614 Jan 99