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)

Intestinal epithelium absorbs calcium by an energy-dependent cellular process that is stimulated by 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. Calcium entry across the brush border is driven by existing electrochemical gradients; exit across the basolateral membrane against these same gradients is driven by a calcium-activated ATPase, sodium-calcium exchange, or both. The specific cellular sites of 1,25(OH)2D3 action remain to be identified. Calcium transport is independent of phosphate and influenced by sodium. Sodium may alter calcium transport at the brush border through alterations of the transmembrane electrical gradient and at the basolateral membrane by exchange with intracellular calcium. The segmental distribution of calcium active transport is heterogeneous, with maximal flux rates in the proximal portions of small intestine and colon and net secretion in mid- and distal small intestine and mid- and distal colon. 1,25(OH)2D3 converts regions of net secretion in ileum and colon to net absorption. 1,25(OH)2D3-stimulated active phosphate transport is largely confined to areas of low-calcium transport, with maximal phosphate absorption in jejunum, the site of maximal calcium secretion. Calcium secretion, primarily in jejunum and ileum, is nonsaturable, may follow the paracellular pathway, and is stimulated by mucosal sodium and somatostatin.
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PMID:Factors that influence absorption and secretion of calcium in the small intestine and colon. 388 91

Somatostatin and gastrin release into the gastric lumen was investigated in anaesthetized, vagally intact rats. The stomach was perfused at a flow rate of 0.5 mL.min-1. During perfusion with 0.1 M HCl or buffers of varying pH the somatostatin ans gastrin concentrations in the perfusate were less than 10 pg.mL -1 and approximately 30 pg.mL-1, respectively. Peptone caused a gastrin concentrations in the perfusate were less than 10 pg.mL-1 and approximately 30 pg.mL-1, respectively. Peptone caused a slight pH-independent increase in somatostatin release; gastrin release was unchanged despite an increase in serum gastrin from a basal of 15 +/- 4 to 155 +/- 34 pg.mL-1 during peptone stimulation. intravenous infusion of carbachol (1 microgram.kg-1.min-1) strongly stimulated luminal somatostatin and gastrin release (from 5 +/- 1 to 192 +/- 52 pg.mL-1 and from 27 +/- 5 to 198 +/- 41 pg.mL-1, respectively) during perfusion with 0.1 M HCl. Phosphate buffer perfusion at pH 7.5 abolished the cholinergic-mediated somatostatin release but the gastrin response was unaffected. It is suggested that changes of luminal hormone concentrations in the rat stomach do not reflect the secretory activity of the endocrine cells in the gastric mucosa.
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PMID:Somatostatin and gastrin release into the gastric lumen in rats. 611 61

Mouse cerebral cortex slices will synthesize [3H]glycogen in vitro. Vasoactive intestinal polypeptide (VIP) stimulates the enzymatic breakdown of this [3H]glycogen. The concentration giving 50% of maximum effectiveness (EC50) is 26 nM. Under the same experimental conditions norepinephrine also induces a concentration-dependent [3H]glycogen hydrolysis with an EC50 of 500 nM. The effect of VIP is not mediated by the release of norepinephrine because it is not blocked by the noradrenergic antagonist d-1-propranolol and is still present in mice in which an 85% depletion of norepinephrine was induced by intracisternal 6-hydroxydopamine injections. Other cortical putative neurotransmitters such as gamma-aminobutyric acid, aspartic acid, glutamic acid, somatostatin, and acetylcholine (tested with the agonist carbamylcholine) do not induce a breakdown of [3H]glycogen. This glycogenolytic effect of VIP and norepinephrine, presumed to be mediated by cyclic AMP formation, should result, at the cellular level, in an increased glucose availability for the generation of phosphate-bound energy. Given the narrow radial pattern of arborization of the intracortical VIP neuron and the tangential intracortical trajectory of the noradrenergic fibers, these two systems may function in a complementary fashion: VIP regulating energy metabolism locally, within individual columnar modules, and norepinephrine exerting a more global effect that spans adjacent columns.
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PMID:Vasoactive intestinal polypeptide induces glycogenolysis in mouse cortical slices: a possible regulatory mechanism for the local control of energy metabolism. 611 64

Certain neurons in the brain are specifically and intensely stained by a histochemical method which demonstrates nicotinamide adenine dinucleotide phosphate NADPH-diaphorase activity. The cell types containing this enzyme in certain areas of the rat forebrain were examined by combining NADPH-diaphorase histochemistry with the indirect immunofluorescence technique. Neurons containing somatostatin- or avian pancreatic polypeptide (APP)-like immunoreactivities were found throughout the forebrain including the striatum and neocortex. These two neuropeptides were also found to coexist in many telencephalic neurons. After photography, the sections processed for immunohistochemistry were stained for NADPH-diaphorase activity by a histochemical method. It was found that within the striatum all of the neurons that were selectively stained by this technique also contained both somatostatin- and APP-like immunoreactivities. Also in the neocortex NADPH-diaphorase was found only in those neurons displaying somatostatin- or APP-like immunoreactivity. In other brain regions such as the nucleus laterodorsalis tegmenti, NADPH-diaphorase-containing cells did not contain these neuropeptides. The results indicate that NADPH-diaphorase histochemistry provides a simple, reliable, histochemical method to demonstrate those striatal neurons in which somatostatin- and APP-like immunoreactivities coexist. The selective occurrence of this enzyme within these neurons may provide a useful target for pharmacological studies of these neuropeptide-containing cells.
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PMID:NADPH-diaphorase: a selective histochemical marker for striatal neurons containing both somatostatin- and avian pancreatic polypeptide (APP)-like immunoreactivities. 613 31

Striatal neurons containing both somatostatin- and avian pancreatic polypeptide (APP)-like immunoreactivities have been shown to be selectively stained by the histochemical method for nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase activity. In the present study, we have utilized this histochemical technique to examine the morphology of these striatal neurons at the light and electron microscopic levels. Our results indicate that the striatal somatostatin/APP/NADPH-diaphorase neurons occur throughout the striatum and have long, aspiny dendrites, oval, invaginated nuclei with prominent nucleoli, and receive few axosomatic contacts. These cells appear to correspond to a population of medium-sized aspiny interneurons reported previously in Golgi and electron microscopic studies of the striatum.
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PMID:Striatal neurons containing both somatostatin- and avian pancreatic polypeptide (APP)-like immunoreactivities and NADPH-diaphorase activity: a light and electron microscopic study. 613 32

We have studied the effects of somatostatin on lipid metabolism in liver and adipose tissue of fasted mice. The animals were injected subcutaneously with 8 micrograms somatostatin and killed 5 min after injection. In vivo incorporation of [14C]acetate into triglycerides in both tissues and into hepatic cholesterol was significantly enhanced by somatostatin. Concomitantly, a decrease of triglyceride lipase activity was observed, which corresponds well with the variation undergone by cyclic AMP-protein kinase system. In addition, a marked increase of serum cholesterol levels was observed. Additionally, in vitro experiments were also performed by employing 2.4 X 10(-6) M somatostatin. The results showed that the direct effect of somatostatin on liver seems to be a decrease in acetate uptake. The results obtained with the adipose tissue were similar to those obtained in in vivo conditions. On the other hand, when somatostatin was administered in vivo, the ability to incorporate ortho[32P]phosphate into phospholipids was enhanced in both tissues. Likewise in the in vitro experiments with [14C]acetate, the somatostatin seems to act by decreasing the ortho[32 P]phosphate uptake in liver. While in adipose tissue the somatostatin only caused a strong increase in the specific activity of phosphatidylcholine. These data demonstrate in fasted mice that somatostatin is able to counteract the lipolytic manifestations of the fasted state.
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PMID:Evidence for a role of somatostatin in lipid metabolism of liver and adipose tissue. 614 94

In isolated hepatocytes of rats with advanced phosphate depletion (serum Pi in controls: 8.79 +/- 0.16 mg/dl; Pi depletion: 2.79 +/- 0.18 mg/dl), diminished gluconeogenesis is observed [controls: 247 +/- 21 nmol X (mg protein)-1 X (30 min)-1; Pi depletion: 174 +/- 15]. In vitro stimulation with glucagon (28 nmol/l) caused a significant rise of glucose production, fall in lactate production, and increase in cAMP content in controls, but did not change glucose or lactate production in Pi depletion despite significant stimulation of cAMP content. This defect was not corrected by pretreating Pi-depleted animals with somatostatin. Impaired basal and glucagon-stimulated glucose production by hepatocytes of Pi-depleted animals was not reversed by incubation in a medium with high Pi content. Insulin (17 nmol/l) did not influence glucose or lactate production in hepatocytes of control or Pi-depleted animals. Epinephrine (10(-6) M) caused a significant stimulation of glucose production in control animals which was inhibited both by phenoxybenzamine (10(-4) M) and propranolol (10(-3) M). Epinephrine-mediated increase of glucose production with pyruvate (10 mM) as substrate was reduced but still demonstrable in hepatocytes of phosphate-depleted animals in parallel with a significant rise of hepatocellular cAMP concentration. Various concentrations of bovine PTH1-34 failed to affect cAMP concentration, glucose or lactate production in Pi-depleted animals and glucose or lactate production in controls. Impaired basal and stimulated (glucagon and epinephrine) glucose production despite adequate cellular cAMP generation points to steps distal to adenylate cyclase as the cause of disturbed hepatic gluconeogenesis in phosphate depletion.
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PMID:Effect of phosphate depletion on gluconeogenesis in isolated rat hepatocytes. 614 23

Reversed-phase high-performance liquid chromatography (HPLC) is examined as a method for separating pancreatic peptides. The method was based on gradient elution with acetonitrile in an acid phosphate buffer (pH 3.10). Apart from human and porcine insulin all the other peptide standards tested (thyrotropin-releasing factor, vaso-active intestinal polypeptide, human C-peptide, porcine C-peptide, somatostatin, porcine glucagon, porcine proinsulin and porcine pancreatic polypeptide) could be separated simultaneously in 40 minutes with a binary gradient composed of five linear segments and increasing from 0 to 60% acetonitrile. Human and porcine insulin could be almost completely resolved by a minimal reduction in the steepness of the acetonitrile gradient. Repeated injections of human C-peptide and porcine insulin resulted in a coefficient of variation of less than 1.5% in the retention times. The use of 125I-labelled peptides gave recoveries exceeding 90%. HPLC of acid ethanol extracts of autopsy pancreases from three infants showed that the immunoreactivity of the peptides measured remained unaffected by the chromatography. Both immunoreactive C-peptide and immunoreactive insulin (IRI) were recovered in two peaks, the second common peak representing proinsulin and amounting to 6.5 to 8.4% of total IRI. Immunoreactive glucagon was eluted in a single peak. Chromatography of plasma extracts from two infants of diabetic mothers demonstrated that proinsulin accounted for 59-63% of total IRI, while insulin was separated into two peaks corresponding to the standards of human insulin and porcine insulin. These results indicate that reversed -phase HPLC is a method with a good reproducibility and a high recovery applicable to the rapid and effective separation of pancreatic peptides from biological extracts.
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PMID:Analysis of pancreatic peptide hormones by reversed-phase high-performance liquid chromatography. 614 91

The effects of a zinc phosphate suspension of a long-acting, reportedly selective somatostatin analog, Des-Ala1,Gly2 [His4,5,D-Try]-somatostatin (100 micrograms/kg) on postprandial plasma glucose, glucagon, xylose and triglyceride levels were evaluated in alloxan diabetic dogs. Compared to the analog in aqueous solution, the zinc phosphate suspension had a more gradual onset of action in suppressing plasma glucose and xylose levels but a similar onset of action on suppression of plasma triglyceride and glucagon responses. On all these responses, the zinc suspension had a duration of action (greater than 6 hrs) at least three times as long as the aqueous solution. We conclude that such a somatostatin analog in zinc phosphate suspension may have a sufficient duration of action to be useful as an adjunct to insulin in the treatment of diabetes mellitus.
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PMID:Effect of a zinc phosphate suspension of a long-acting somatostatin analog on postprandial plasma glucose, triglyceride and glucagon concentrations in alloxan diabetic dogs. 615 Nov 11

Paired indirect immunoenzyme staining based on primary antisera from the same species was performed sequentially without intermediate antibody elution. The first antigen was labelled brown by an immunoperoxidase procedure (either the two-stage indirect method, the unlabelled antibody peroxidase-antiperoxidase method, or the avidin-biotin bridge method using diaminobenzidine (DAB) and hydrogen peroxide as the substrates. The second antigen was labelled blue by applying a two-stage indirect immuno-alkaline phosphatase procedure using naphthol AS phosphate and Fast Blue BB salt as the substrate. In this way, polyclonal mucosal immunocytes were revealed in distinctly contrasting colours when stained for kappa and lambda light chains. Glucagon and somatostatin (D) cells in human pancreatic islets, and gastrin and D cells in human gastric antral glands, were likewise clearly differentiated. Conversely, a mixed colour appeared in some immunocytes after staining for alpha and kappa chains. However, unbalanced colour mixing was sometimes difficult to interpret, and additional experiments demonstrated that unwanted interactions could take place between the two sequences of reagents if the density of the DAB deposits was insufficient. These pitfalls were incompatible with unequivocal double staining in the same cell. Nevertheless, paired staining could be conveniently applied with the described procedures when prior knowledge had established that the antigens in question were located in separate cells.
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PMID:Paired indirect immunoenzyme staining with primary antibodies from the same species. Application of horseradish peroxidase and alkaline phosphatase as sequential labels. 620 74


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