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 effects of intraarterial administration of somatostatin upon intestinal blood flow, intestinal capillary surface area, oxygen consumption and intestinal motor activity were measured in anesthetized dogs. Blood flow to the segment of distal ileum was measured with an electromagnetic blood flow meter, and arteriovenous oxygen difference (AVO2) was determined spectrophotometrically. Intestinal oxygen consumption was calculated as the product of AVO2 and total blood flow. The clearance of 86Rb was measured to estimate the density of the perfused intestinal capillaries. Changes in blood flow distribution were estimated from the distribution of radiolabelled microspheres. Intestinal motor activity was monitored from changes in intraluminal pressure. Somatostatin induced a dose-related decrease in intestinal blood flow, capillary surface area and intestinal oxygen consumption. A significant increase in intestinal motor activity was also observed. The data of this study indicate that somatostatin acts on smooth muscle of both arterioles and precapillary sphincters and results in a potent vasoconstriction in the intestinal microcirculation.
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PMID:Effects of somatostatin on intestinal circulation and oxygen consumption. 257 89

Somatostatin (SS) in 10(-9)-10(-7) M concentrations stimulated the lysis and inhibited the incorporation of IgG2a-coated 51Cr-labeled sheep red blood cell (SRBC) by rat peritoneal macrophages (PM). The intracellular killing capacity of PM remained unchanged. The enhancement of Fc receptor (R) activity and generation of active oxygen species were found to be responsible for the antibody-dependent cellular cytotoxicity (ADCC)-stimulating effect of SS. It was demonstrated that the stimulation of ADCC was abolished by the calmodulin inhibitor trifluoperazine (TFP), whereas it proved to be independent of the Ca2+ uptake. In addition, SS in the ADCC-stimulating concentrations diminished the intracellular cAMP generation and progressively increased the cGMP level. In higher (10(-6)-10(-7) M) concentrations, SS had a controversial effect on PM: it inhibited ADCC through the activation of both the adenylate cyclase and Ca2+ influx.
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PMID:The mechanism of antibody-dependent cellular cytotoxicity stimulation by somatostatin in rat peritoneal macrophages. 285 14

The effects of cold exposure on mean arterial pressure (MAP), heart rate (HR) and oxygen consumption (VO2) were examined in conscious, unrestrained rats receiving intracerebroventricular (i.c.v.) injections of bombesin or appropriate control solutions. Cold exposure elicited significant elevations of MAP, HR and VO2 in control-treated rats. I.c.v. administration of bombesin produced dose-related suppressions of cold-induced elevations of HR and VO2, but not MAP. The central nervous system (CNS)-selective somatostatin analog, ODT8-SS, injected i.c.v., reversed the effects of bombesin on HR and VO2 during cold exposure. Intravenous administration of atropine methyl nitrate did not antagonize the effects of bombesin on HR and VO2 during cold exposure. HR and VO2 were strongly correlated in bombesin-treated rats suggesting that this peptide may prevent cold-induced elevations of VO2 through a CNS action on cardiac function.
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PMID:Central nervous system effects of bombesin on the cardiovascular response to cold exposure. 286 99

Cysteamine (CSH; beta-mercaptoethylamine) is known to deplete pancreatic somatostatin without affecting the insulin or glucagon content. It may therefore be useful for studies of intra-islet regulation of hormone release. In the present study injection of CSH (60 mg/kg body weight) to mice decreased the somatostatin content of their isolated pancreatic islets to 50% in 1 h and 30% in 4 h as compared to islets of non-injected controls. Exposure of isolated mouse islets to CSH (100 micrograms/ml) for either 0.5 h followed by incubation in control medium for 3.5 h, or continuously for 4 h, decreased the somatostatin content to about 40% of the controls. There was no change in the islet content of insulin or glucagon. Islets pretreated with CSH (100 micrograms/ml) for 1 h in vitro showed a decreased glucose stimulation of both oxygen consumption and glucose oxidation. Measurements of insulin release after a similar preincubation of the islets indicated an increased basal release and an attenuated glucose stimulation. It is concluded that CSH rapidly decreases islet somatostatin both in vivo and in vitro. This depletion may lead to a loss of tonic inhibition by islet somatostatin on basal insulin release. It is, however, more plausible that the increased basal insulin release reflected a direct effect of CSH on the islet beta-cells.
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PMID:Rapid depletion of somatostatin in isolated mouse pancreatic islets after treatment with cysteamine. 286 62

This experiment was performed to determine if plasma glucose homeostasis is maintained in normal human volunteers during light exercise (40% maximal oxygen consumption [VO2 max]) when changes in insulin and glucagon are prevented. Hormonal control was achieved by the infusion of somatostatin, insulin, and glucagon. Glucose kinetics and oxidation rates were determined with stable isotopic tracers of glucose, and by indirect calorimetry. Two different rates of replacement of insulin and glucagon were used; in one group, insulin was clamped at 19.8 +/- 2.6 microU/ml (high-insulin group), and in the other group insulin was clamped at 9.2 +/- 1.3 microU/ml (low-insulin group). Glucagon was maintained at 261 +/- 16.2 and 124 +/- 6.4 pg/ml, respectively, in the high-insulin and low-insulin groups. Without hormonal control, plasma glucose homeostasis was maintained during exercise because the increase in glucose uptake was balanced by a corresponding increase in glucose production. When changes in insulin and glucagon were prevented, plasma glucose concentration fell, particularly in the high-insulin group. Glucose uptake increased to a greater extent than when hormones were not controlled, and glucose production did not increase sufficiently to compensate. The increase in glucose uptake in the hormonal control groups was associated with an increased rate of glucose oxidation. When euglycemia was maintained by glucose infusion in the hormonal control subjects, the modest increase in glucose production that otherwise occurred was prevented. It is concluded that during light exercise there must be a reduction in insulin concentration and/or an increase in glucagon concentration if plasma glucose homeostasis is to be maintained. If such changes do not occur, hypoglycemia, and hence exhaustion, may occur.
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PMID:Role of changes in insulin and glucagon in glucose homeostasis in exercise. 286 53

We studied the influence of hyperglycemia on glucose homeostasis in man by determining the effect of graded hyperglycemia on peripheral glucose uptake and systemic metabolism in the presence of basal and increased serum insulin concentrations in 10 normal men. This was achieved by the simultaneous application of forearm and clamp techniques (euglycemic and hyperglycemic) during the combined iv infusion of somatostatin, glucagon, and insulin. While mean (+/- SE) basal serum insulin levels (14 +/- 2 microU/ml) were maintained, the elevation of fasting arterial glucose concentrations (90 +/- 1 mg/dl) to 146 +/- 1 and 202 +/- 1 mg/dl (each for 120 min) increased forearm glucose uptake (FGU) only modestly from 0.06 +/- 0.01 to 0.15 +/- 0.02 and then to 0.24 +/- 0.03 mg/100 ml forearm X min, respectively. During physiological hyperinsulinemia (47 +/- 3 microU/ml), the influence of similar graded hyperglycemia on FGU was considerably enhanced. At plasma glucose concentrations of 90 +/- 1, 139 +/- 1, and 206 +/- 1 mg/dl, FGU rose to 0.33 +/- 0.05, 0.59 +/- 0.07, and 0.83 +/- 0.12 mg/100 ml forearm X min, respectively. The glucose infusion rate required to maintain the glucose clamp with basal insulin levels was 1.08 +/- 0.20 and 2.67 +/- 0.39 mg/kg X min at glucose concentrations of 146 +/- 1 and 202 +/- 1 mg/dl, respectively. During physiological hyperinsulinemia, however, the glucose infusion rate required was 4.15 +/- 0.39, 9.45 +/- 1.05, and 12.70 +/- 0.81 mg/kg X min at glucose levels of 90 +/- 1, 139 +/- 1, and 206 +/- 1 mg/dl, respectively. Lactate concentrations rose significantly during hyperglycemia, but the rise in the presence of increased insulin concentrations (from 0.72 +/- 0.06 to 1.31 +/- 0.11 mmol/liter; P less than 0.001) considerably exceeded the increment (from 0.74 +/- 0.05 to 0.92 +/- 0.03 mmol/liter) with basal insulin levels. While both FFA and glycerol concentrations were immediately reduced by euglycemic hyperinsulinemia, the fall in FFA during hyperglycemia in the presence of basal insulin levels preceded the decrease in glycerol concentrations by 45 min. Forearm oxygen consumption did not change throughout the study.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The influence of graded hyperglycemia with and without physiological hyperinsulinemia on forearm glucose uptake and other metabolic responses in man. 287 53

The influence of a long-acting somatostatin octapeptide analogue (SMS 201-995) on splanchnic circulation and metabolism has been studied in healthy subjects and in patients with liver cirrhosis. In healthy subjects doses of 5, 10, 50, or 100 micrograms SMS and in the cirrhotic patients 25 micrograms SMS were infused intravenously during 1 h. Measurements were obtained before, during, and for 1 h after SMS infusion. SMS infusion in healthy subjects resulted in a 25-35% reduction in hepatic blood flow. This effect was largely independent of the dose used. Splanchnic oxygen uptake was unchanged before and during SMS infusion. Insulin and glucagon levels fell markedly in response to SMS administration, and the blood concentration and splanchnic output of glucose decreased transiently. Patients with liver cirrhosis responded to SMS infusion similarly to the healthy subjects. Hepatic blood flow decreased by 25-35% and remained suppressed for at least 1 h after infusion. Wedge hepatic venous pressure was 18 +/- 2 mm Hg in the basal state and decreased progressively during and after SMS infusion (60 min after infusion, 15 +/- 2 mm Hg; P less than 0.01). The marked hyperinsulinaemia and hyperglucagonaemia seen in the basal state decreased significantly during SMS administration. As in the case of the controls, blood concentration and splanchnic output of glucose fell transiently during and after SMS infusion. It is concluded that SMS exerts a marked and prolonged suppressive effect on hepatic blood flow in both healthy subjects and patients with liver cirrhosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The influence of a long-acting somatostatin analogue on splanchnic haemodynamics and metabolism in healthy subjects and patients with liver cirrhosis. 287 92

The influence of SMS 201-995 (octreotide, Sandostatin), a long-acting somatostatin analogue, on splanchnic haemodynamics was studied in 15 patients with liver cirrhosis and in 5 healthy individuals before, during, and after 60 min of intravenous SMS infusion (25 and 50 micrograms/h, respectively). No adverse effects of the SMS infusion were seen. In the basal state the estimated hepatic blood flow was 1.04 +/- 0.08 l/min (mean +/- SE) in the patients and 1.62 +/- 0.09 l/min (P less than 0.001) in the controls. At 15 min after the beginning of the infusion the blood flow had already decreased by 15-30% (P less than 0.05-0.01). The reduction was more marked in controls than in patients, and it persisted in both groups during and for 60 min after the infusion. Wedged hepatic venous pressure, measured in the patients, was 20 +/- 2 mmHg in the basal state and 18 +/- 1 mmHg during the infusion (P less than 0.05), and it remained at this level for 60 min after the infusion. Free hepatic venous pressure was unchanged throughout the study. Splanchnic oxygen uptake was similar in the two groups in the basal state and remained unaltered during and after SMS infusion. Both heart rate and arterial systolic and diastolic blood pressure remained unchanged during SMS administration. In summary, SMS infusion results in a fall in hepatic blood flow and a slight but significant decrease in wedged hepatic venous pressure, whereas no effect was noted on the systemic circulation.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Haemodynamic effects of a long-acting somatostatin analogue in patients with liver cirrhosis. 289 Nov 84

This study examined the relationship between postnatal metabolic and hormonal changes and the accompanying rapid increase in mitochondrial adenine nucleotide content (ATP + ADP + AMP) in rabbit liver. The cytosolic NAD+/NADH concentration ratio, calculated from tissue pyruvate and lactate values, increased linearly 6.6-fold during the 1st postnatal h. The mitochondrial NAD+/NADH concentration ratio, calculated from tissue acetoacetate and beta-hydroxybutyrate values, increased 28-fold by 30 min postnatal. These changes in NAD+/NADH suggest that tissue oxygenation occurs rapidly and that oxygen supply rather than substrate supply is limiting for mitochondrial respiration in the immediate postnatal period. The normal increase in mitochondrial adenine nucleotide content that occurs within 2 h after birth was inhibited by hypoxia (5% O2). Glucagon stimulated the postnatal increase in mitochondrial adenine nucleotides but had no effect in combination with hypoxia. Both glucose and somatostatin injections inhibited the increase in mitochondrial adenine nucleotides and increased the insulin-to-glucagon ratio. Isoproterenol or dibutyryl cAMP stimulated, but propranolol did not inhibit, the normal increase in mitochondrial adenine nucleotide content. Phentolamine did not stimulate the postnatal accumulation of adenine nucleotides. In summary, the results show that the insulin-to-glucagon ratio is probably the most important hormone regulator of the rapid recompartmentation of adenine nucleotides into the mitochondrial matrix and that tissue oxygenation is strictly permissive for this hormone effect in the first 2 h after birth.
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PMID:Regulation of mitochondrial adenine nucleotide content in newborn rabbit liver. 289 2

A total of ten 6-month-old male rhesus monkey (Macaca mulatta) infants, born full-term, were positive-pressure ventilated with greater than 95% oxygen or room air (controls). A protocol was used which closely simulated pediatric intensive care. To test if regulatory peptides were affected by the oxygen treatment, and to search for an early marker of oxygen toxicity, lung tissue samples and systemic mixed venous blood were collected at 6, 12 and 24 hours after onset of treatment. The peptides, gastrin releasing peptide (GRP), calcitonin gene-related peptide (CGRP), peptide YY (PYY), vasoactive intestinal peptide (VIP) and somatostatin (SOM), were quantitated in lung tissue extracts and plasma using radioimmunoassay. Lung tissue GRP, CGRP, and PYY levels appeared to decrease gradually with time, perhaps as a result of the positive pressure ventilation procedure. GRP and CGRP levels decreased less among monkey infants ventilated with oxygen, thus they were significantly higher at 24 hours than in air ventilated controls. VIP levels were significantly lower among tests compared to controls at that time. Blood peptide levels did not change with oxygen treatment. These results suggest that tissue concentrations of certain pulmonary regulatory peptides can become altered by ventilation with greater than 95% oxygen. A blood borne peptide marker was not identified.
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PMID:Oxygen toxicity in the infant rhesus monkey: effects on regulatory peptides in lung and blood. 290 54


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