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)

The mechanisms controlling secretion of glucagon and other pancreatic hormones were studied in a patient affected with multihormone-secreting islet-cell tumor. Fasting glucagon levels (3,000 pg./ml.) rose to 10 ng./ml. following arginine stimulation. While oral glucose load and intravenous glucose infusion did not suppress glucagon secretion, insulin administration induced a prompt depression in glucagon levels. Glucagon, insulin, and gastrin levels were suppressed by somatostatin while calcium infusion caused a paradoxical increase. It is suggested that only some of the stimulation-inhibition mechanisms were conserved in this case of glucagon-secreting pancreatic tumor.
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PMID:Suppression and stimulation mechanisms controlling glucagon secretion in a case of islet-cell tumor producing glucagon, insulin, and gastrin. 0 26

The effects of a 0.5 g/kg body weight arginine infusion on plasma inorganic phosphates and potassium were examined in nineteen normal subjects. Plasma phosphorus displayed a highly significant (p less than 0.001) fall with a maximum depression below baseline of 1.11 +/- 0.15 mg/100 ml or 33 +/- 3% (mean +/- SEM); there was a significant correlation (p less than 0.01) between this fall and the insulin peaks induced by arginine. Plasma potassium levels displayed a distinct and significant increase in eleven of the twelve subjects studied; the maximum increase above baseline was 1.02 +/- 0.14 mEq/1 or 27 +/- 4.5% (p less than 0.001). No change occurred in blood pH values determined in four subjects. In six normal subjects, the test was repeated with the addition of somatostatin (250 micrograms bolus, followed by 500 micrograms/hr), which abolished the insulin and growth hormone response to arginine. It also abolished the fall in plasma phosphorus but appeared (if anything) to augment the increase in potassium. These findings show that arginine is responsible for a fall in plasma phosphorus related to the insulin response, and for an increase in plasma potassium of clinical significance, the mechanism(s) of which, however, are still obscure.
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PMID:Arginine-induced hypophosphatemia and hyperkaliemia in man. 4 74

In human placental explants cultured in vitro, dopamine inhibited human chorionic somatomammotropin (hCS) secretion into the culture media. In the control flasks, the level of hCS secretion was 130.5 +/- 7.8 micrograms/g tissue (n = 6). When 1 mM dopamine was added, hCS levels decreased to 80.2 +/- 11.5 micrograms/g tissue (P less than 0.01). Dopamine (5 and 10 mM) further lowered hCS levels. In contrast, 1 mM pimozide enhanced hCS secretion by 2-fold as compared to control levels (248.2 +/- 44.8 vs. 130.5 +/- 7.8, P less than 0.02). The simultaneous addition of dopamine did not alter the stimulatory effect of pimozide on hCS secretion. In separate experiments, arginine (1 and 5 mM) and somatostatin (1 microgram/ml culture media) did not alter hCS secretion from placental explants. These results suggest that hCS secretion is modulated by dopaminergic receptors.
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PMID:In vitro effect of dopamine and pimozide on human chorionic somatomammotropin (hCS) secretion. 4 61

The secretion of GH in two siblings with clinical dwarfism and high GH plasma levels (the mean of several basal values; 233.83 ng/ml in patient A and 178.16 in patient B has been studied with several dynamic tests. An arginine infusion increased GH levels in both cases (+193.55% for A, +140.27% for B). No significant modifications were obtained with oral glucose tolerance test +18.70% for A, +24.32% for B). A bolus of somatostatin almost completely prevented the rise in GH levels in response to arginine. Pretreatment with bromocryptine clearly increased basal GH plasma levels (A, +58.66%; B, +56.03%) and the response to arginine. As in the case of a normal hypothalamus, the hypothalamus of Laron's syndrome responds to arginine and bromocryptine, with GH elevations. Somatostatin suppresses GH levels. A lack of response to glucose can be considered as a nonspecific effect of the very low biological activity of the stimulus in a hyperstimulated hypothalamus. We suggest that GH secretion by the hypothalmo pituitary system in Laron's syndrome is normal, and that GH hyperproduction may be due to a generalized defect in GH receptors or to the low levels of somatomedin.
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PMID:GH secretion in two siblings with Laron's dwarfism: the effects of glucose, arginine, somatostatin, and bromocryptine. 4 65

Extracts of homogenates of rat, mouse, rabbit, and human submaxillary salivary glands contain a significant quantity of a material with glucagon-like immunoreactivity. Fractionation of this material on columns of Sephadex G-100 reveals a single peak immediately following a gamma globulin marker but in advance of a rat growth hormone marker, crystalline amylase, and isotopically labeled porcine insulin and glucagon. This material, which is urea stable, shows identical immunoassay dilution curves when measured with the highly specific K-30 glucagon antiserum. Study of paired glands in vitro shows that low concentrations of glucose stimulate and high concentrations of glucose suppress release of this material. Arginine promotes brisk release in vitro. Somatostatin does not influence arginine-stimulated secretion and insignificantly suppresses basal release in vitro. These findings lend support to previous speculations that the salivary glands may possess endocrine as well as exocrine functions. Salivary gland glucagon may also be the source of circulating glucagon recently reported in pancreatectomized and eviscerated rats.
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PMID:Salivary gland hyperglycemic factor: an extrapancreatic source of glucagon-like material. 6 92

Growth hormone regulation was studied in 10 patients with Huntington's disease after intravenous administration of arginine. In 20 control subjects arginine infusion resulted in a rise of plasma growth hormone levels from a mean baseline value of 3.2+/-0.6 ng/ml to a peak level of 17.6+/-2.7 ng/ml at 60 min. Growth hormone rise in the majority of patients with Huntington's disease was clearly intact and significantly greater than normal in magnitude, increasing from the baseline level of 2.6+/-0.5 ng/ml to a peak level of 28.3+/-3.7 ng/ml at 60 min (P = less than 0.05). Carbohydrate tolerance of these patients was previously examined, and 4 with normal glucose tolerance and normal insulin responses to arginine infusion had growth hormone levels significantly higher than controls at 30 min. Six patients with impaired carbohydrate tolerance and exaggerated insulin responses to arginine had significantly higher growth hormone responses at 30 min and also at 60 min. Neuronal degeneration of several hypothalamic nuclei has been reported in Huntington's disease. The observations that growth hormone responds in an exaggerated fashion to stimulation by arginine infusion or falling glucose levels as previously described may be explained by intrahypothalamic dysfunction such as impairment of somatostatin secretion.
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PMID:Exaggerated growth hormone response to arginine infusion in Huntington's disease. 12 87

To determine whether synthetic somatostatin originally isolated from sheep hypothalamus can inhibit hormone secretion in the same species, we measured plasma levels of GH, insulin, glucagon, and glucose of normal sheep under a variety of experimental conditions in the presence and absence of somatostatin infusion. An oral dose of 2.5 mg./kg. 3,5-dimethypyrazole increase plasma GH from 10.9 to 376.9 ng. per milliliter, which was suppressed by 50 per cent and 80 per cent with 0.5 and 1 mg. synthetic cyclic somatostatin, respectively. Linear somatostatin (0.5 mg.) was without effect in two animals tested. Propionate (0.5 mmole per kilogram) and arginine (10 gm.) induced a rise in plasma insulin and GH, and glucagon was effectively blocked by cyclic somatostatin (0.5 mg.). Similarly, somatostatin inhibited glucose, and glucagon provoked GH and insulin secretory responses without affecting glucose or FFA levels. Somatostatin had no effect on the disappearance of injected glucagon. Finally, addition of somatostatin to incubation media prevented PGE promoted GH release, and suppressed cyclic AMP accumulation, although to a lesser extent, in sheep anterior pituitary pieces. In view of the large amounts required to suppress stimulated hormone release and the general lack of specificity of somatostatin, it is suggested that this peptide may have a functional role only in the release of hormones of the pituitary, where it could occur in relatively high local concentrations. Its inhibition of extrapituitary hormone secretion may be purely a pharmacologic effect that, nevertheless, suggests an interference with a step common to the secretory process of hormones.
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PMID:Studies on growth hormone secretion. VII. Effects of somatostatin on plasma GH, insulin, and glucagon in sheep. 16 76

The inhibitory actions of somatostatin (100 ng./ml.) on insulin release, stimulated by high glucose (20 mM), and on glucagon release, stimulated by arginine (15 mM), were studied with two in vitro systems: the isolated perifused rat islets prepared by the collagenase procedure and the isolated perfused rat pancreas. Suppression of arginine-induced glucagon release by glucose (20 mM) and glyceraldehyde (5 mM) was also assessed in both systems. With the perfused pancreas, somatostatin caused 32 per cent inhibition of glucose-mediated insulin release and inhibited arginine-induced glucagon release by 72 per cent. In the same system, glucose and glyceraldehyde were similarly potent inhibitors of arginine-induced glucagon secretion. In contrast to the isolated perfused pancreas, there was no significant somatostation suppression of glucose-induced insulin release or arginine-induced glucagon release whether the inhibitor was present prior to or was added during stimulation by glucose or arginine. Furthermore, glucose was only minimally active and glyceraldehyde ineffective in inhibiting glucagon secretion due to arginine in the perifusion system. The most plausible explanation for the difference in the endocrine response of islet cells in the two types of widely used in vitro systems is that the alpha and beta cells have lost inhibitory receptors in the plasma membrane as a result of the collagenase isolation technic.
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PMID:Comparison of alpha- and beta-cell secretory responses in islets isolated with collagenase and in the isolated perfused pancreas of rats. 17 Nov 90

The effect of somatostatin on insulin release by incubated slices of rat pancreas was studied. Somatostatin inhibited insulin release induced by arginine/glucose (A/G), glucagon, glibenclamide, pentoxifyllin, 3',5'-adenosine monophosphate (cAMP), phentolamine, and KCl. When A/G was used as a stimulus, the quantial inhibitory effect of somatostatin was not neutralized by progressively increasing glucose concentrations. The alpha adrenergic blocking agent phentolamine, the phosphodiesterase inhibitors theophylline (10 mM) or pentoxifyllin (10 mM), and KCl partially reversed the inhibitory effect of somatostatin on A/G stimulation. The maximal reversal of somatostatin inhibition was obtained when the slices of pancreas were stimulated with A/G in the presence of the calcium ioniphore A23187 plus ATP. These results suggest that the inhibitory effect of somatostatin on insulin secretion could result from calcium translocation in pancreatic beta cells.
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PMID:Studies on the mode of action of somatostatin on insulin secretion. 19 19

A case of glucagonoma syndrome with necrolytic migratory erythema, glossitis, anemia, hyperglucagonemia and a malignant, pancreatic A-cell tumour in a 68-year-old male is described. Gel filtration of the highly elevated circulating glucagon immunoreactivity (2200 pg/ml) demonstrated 60% pancreatic glucagon and 30% "proglucagon". Metabolic studies before operation demonstrated suppression of the total plasma glucagon concentration on oral glucose tolerance test, unchanged total plasma glucagon concentration during intravenous glucose tolerance test and insulin-induced hypoglycemia. Administration of arginine was followed by a rise in both the pancreatic glucagon and the "proglucagon", whereas alanine increased only the pancreatic glucagon. The plasma somatostatin level was immeasurable preoperatively. Somatostatin infusion completely suppressed the release of the pancreatic glucagon but did not significantly affect the "proglucagon". After removal of the tumour the skin lesions disappeared and the total plasma glucagon values fell to normal levels (120 pg/ml). Also, other abnormal laboratory findings returned to normal, including the preoperatively observed renal glucosuria.
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PMID:Metabolic studies and glucagon gel filtration pattern before and after surgery in a case of glucagonoma syndrome. 21 26


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