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)

Extracts of mouse hypothalamus made in acid/urea containing protease inhibitors were analyzed for somatostatin immunoreactivity after molecular sieve filtration on Sephadex G-50. Higher molecular weight (higher-M(r)) somatostatin-like forms with apparent molecular weights of 15,000, 10,000, and 6000 could be identified, besides the molecular weight 1600 somatostatin. Immunological identities with somatostatin were unambiguously demonstrated by the analysis of the displacement curves in the radioimmunoassay. The M(r) 15,000, 6000, and 1600 species were purified by affinity chromatography on an anti-somatostatin immune serum covalent conjugate with Sepharose used as immunoadsorbant. After disulfide reduction by dithiothreitol, the size of the M(r) 15,000 and 6000 somatostatin-like species was assessed either by molecular sieve filtration or by polyacrylamide gel electrophoresis. The results indicated that the higher-M(r) somatostatin-like species isolated from the hypothalamus did not result from hormone polymerization by means of disulfide interchange. The processing in vitro of the 15,000 higher-M(r) form of somatostatin was achieved by proteolytic enzymes coeluted with this species during the fractionation of hypothalamic extracts. Under neutral pH conditions the intermediary higher-M(r) forms were generated together with the M(r) 1600 somatostatin-like species. This processing activity could be either strongly inhibited at acidic pH or in acid/urea medium or else eliminated by selective immunoadsorption of the 15,000 higher-M(r) form. Neither trypsin nor the gamma subunit of 7S nerve growth factor was able to produce this processing, suggesting that enzymes with other kinds of specificity may be involved. It is concluded that somatostatin biosynthesis in the mouse hypothalamus may occur via a high-M(r) precursor that is processed into intermediary forms leading to the tetradecapeptide hormone.
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PMID:Higher molecular weight forms of immunoreactive somatostatin in mouse hypothalamic extracts: evidence of processing in vitro. 4 8

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

Somatostatin-like immunoreactivity (SLI) is widely distributed in tissues and biological fluids. To determine whether SLI is also present in amniotic fluid, samples obtained by amniocentesis from 30 normal and 27 abnormal pregnancies were studied by radioimmunoassay. Direct incubation of [(125)I-Tyr(1)]tetradecapeptide somatostatin (SRIF) with amniotic fluid resulted in 89% tracer degradation. Damage was reduced to <5% when samples were acidified and boiled before the assay. With this technique, SLI was detectable in all normal amniotic fluid samples; the mean level at 15-20 wk of gestation (320+/-55 pg/ml, n = 15) being 4.5 times higher than the mean at 32-43 wk (70+/-12 pg/ml, n = 15) (P < 0.001). In cases of preeclampsia (n = 6), gestational diabetes (n = 5), anencephaly (n = 1), and meningomyelocele (n = 1), SLI values were in the normal range, but in one juvenile diabetic and one patient with chronic renal failure, SLI was undetectable (<10 pg/ml). In a pair of monochorionic diamniotic twins, SLI levels were very different (33 and 197 pg/ml), which suggests that fetal factors are more important than materno-placental ones in determining amniotic fluid SLI. Serial dilutions of amniotic fluid showed parallelism with standard SRIF. When concentrates of pooled amniotic fluid were chromatographed on Sephadex G-25 columns, all SLI eluted in the void volume ahead of SRIF even after treatment with 8 M urea and dithiothreitol. This "big" SLI incubated in amniotic fluid showed 100% stability over 24 h at 37 degrees C, whereas SRIF was rapidly inactivated (t((1/2)) congruent with 7 min). Extracts of placenta and fetal membranes contained no SLI, but small amounts (6-20% of total amniotic fluid SLI) were found in cells from fresh fluid. Radioimmunoassay of SLI in extracts of seven paired cord arterial and venous plasma samples showed no arteriovenous gradient consistent with fetal origin of cord blood SLI. It is concluded that (a) amniotic fluid contains SLI which is of fetal origin and (b) normal levels vary with gestational age. The SLI has a higher molecular weight (>/=5,000) and is more stable in amniotic fluid than SRIF.
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PMID:Measurement, characterization, and source of somatostatin-like immunoreactivity in human amniotic fluid. 46 88

The role of glucagon in diabetes was studied in four patients with juvenile-type diabetes during continuous insulin infusion and a diet containing 150 g per day of carbohydrate. During insulin alone, plasma glucagon, measured at two-hour intervals, averaged 182 +/- 34 pg per milliliter, glucose 269 +/- 11 mg per deciliter, glucose excretion 52 +/- 8 g per 24 hours, ketone excretion 1.3 +/- 0.3 mmol per 24 hours, and urea nitrogen 12 +/- 2 g per 24 hours (mean +/- S.E.M.). Somatostatin (2 mg per day) lowered glucagon to 60 +/- 13 pg per milliliter, glucose to 111 +/- 17 mg per deciliter, glucose excretion to 1 +/- 0.7 g per 24 hours, ketone excretion to 0.5 +/- 0.2 mmol per 24 hours and urea nitrogen excretion to 8 +/- 2 g per 24 hours. Replacement of glucagon raised glucagon to 272 +/- 30 pg per milliliter, glucose to 202 +/- 20 mg per deciliter, glucose excretion to 14 +/- 7 g per 24 hours, ketone excretion to 0.8 mmol per 24 hours and urea nitrogen excretion to 11 +/- 2 g per 24 hours. In a subsequent study, similar improvement occurred on a diet of 30 g of carbohydrate daily, when absorption of dietary glucose was negligible. Hyperglucagonemia has an important role in diabetes; its correction reduces diabetic abnormalities to or toward normal.
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PMID:Hyperglucagonemia and its suppression. Importance in the metabolic control of diabetes. 68 75

The effects of short-term (90 min), mid-term (5 days), and long-term (15 days) administration of ammonium acetate (5 mmol/Kg day i.p.) on the somatostatinergic neurotransmitter system of the rat hippocampus have been studied. Scatchard analysis of the binding of 125I-Tyr11-somatostatin to hippocampal dissociated cells indicated that administration of ammonium acetate at the times studied were associated with a decrease in the number of somatostatin receptors in this brain area, whereas the affinity of the same receptors remained unchanged. Administration of ammonium acetate did not affect the levels of somatostatin-like immunoreactivity in the hippocampus. Treatment with N-carbamyl-L-glutamate (1 mmol/Kg, i.p.) plus L-arginine (1 mmol/kg), which lead to the conversion of ammonia into urea, prevented the ammonium acetate-induced changes in somatostatin binding in this brain area. N-carbamyl-L-glutamate plus L-arginine alone had no observable effect on the somatostatinergic system. The decrease in the number of somatostatin receptors induced by ammonium acetate might reflect a decreased sensitivity of the target cells to somatostatin, a phenomenon that could contribute to the depressed neuronal excitability induced by ammonia in the rat hippocampus.
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PMID:Somatostatin binding reduced by ammonium acetate in the rat hippocampus can be reversed by treatment with N-carbamyl-L-glutamate plus L-arginine. 135 63

In membranes of neuroblastoma x glioma (NG108-15) hybrid cells, the photoreactive GTP analog, [alpha-32P] GTP azidoanilide, was incorporated into 39-41-kDa proteins comigrating in urea-containing sodium dodecyl sulfate-polyacrylamide gels with immunologically identified G-protein alpha-subunits, i.e. a 39-kDa Go alpha-subunit, a 40-kDa Gi2 alpha-subunit, and a 41-kDa Gi alpha-subunit of an unknown subtype. The synthetic opioid, D-Ala2,D-Leu5-enkephalin (DADLE), stimulated photolabeling of the 39-41-kDa proteins. In the presence of GDP, which increased the ratio of agonist-stimulated to basal photolabeling, DADLE at a maximally effective concentration stimulated photolabeling of the 39- and the 40-kDa protein 2-3-fold. Somatostatin, adrenaline, and bradykinin were less potent than DADLE and, to varying degrees, stimulated photolabeling of the 40-kDa protein more than that of the 39-kDa protein. Prostaglandin E1 was inactive. The present data represent direct evidence for an activation of endogenous Go and Gi2 via opioid receptors and other receptors in the native membrane milieu.
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PMID:Evidence for opioid receptor-mediated activation of the G-proteins, Go and Gi2, in membranes of neuroblastoma x glioma (NG108-15) hybrid cells. 167 72

The aim of this study was to characterize the effects of prolonged infusion of growth hormone-releasing factor (1-29)NH2 (GRF) on plasma concentrations of hormones and metabolites when administered to control pigs and pigs immunized against somatostatin (SRIF). In the first experiment, eight purebred Yorkshire boars averaging 113 +/- 2 kg BW were immunized against SRIF conjugated to bovine serum albumin (BSA) (n = 4) or BSA alone (n = 4). Somatotropin (ST) response to four rates of GRF infusion (0, 1.66, 5 and 15 ng/min/kg BW) for 6 hr was evaluated using a double balanced 4 x 4 Latin square design. During the 4 hr before infusion, SRIF-immunized animals tended (P = 0.06) to have a higher ST release (613 vs 316 ng.min/ml, SE = 232) than controls. During infusion, GRF elicited a dose-dependent increase in ST release in both squares; the ST response was not better in SRIF-immunized animals than in controls (P greater than 0.05) (1435 vs 880 ng.min/ml; SE = 597). In the second experiment, ten purebred Yorkshire boars (5 controls and 5 SRIF-immunized animals) averaging 69 +/- 2 kg BW were continuously infused with GRF at the rate of 15 ng/min/kg BW for six consecutive d. Under GRF infusion, ST concentrations increased (P less than 0.05) from 805 to 4768 ng.min/ml (SE = 507) from day 1 to day 6 in both SRIF-immunized and control animals. Prolactin levels increased (P less than 0.05) with GRF infusion; pattern of increase was different (P less than .01) overtime in control and SRIF-immunized animals. Thyroxine levels increased from 2.53 to 3.45 micrograms/dl (SE = 0.16) after six d of infusion. Insulin-like growth factor I was higher (P less than 0.05) before (139 vs 90 ng/ml; SE = 11) and during (222 vs 185 ng/ml; SE = 11) GRF infusion in SRIF-immunized animals. A transient increase (P less than 0.05) in glucose and insulin was observed in both groups. Immunization against SRIF had no effect on blood metabolites; however, GRF infusion increased free fatty acids from 157 to 204 microEq/l (SE = 11) and decreased blood urea nitrogen from 4.1 to 3.5 mmol/l (SE = 0.2) from day 1 to day 6, respectively. In summary, active immunization against SRIF in growing pigs increased ST and IGF-I concentrations. Infusion of GRF continuously raised ST levels with days of infusion without any sign of decrease responsiveness.
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PMID:Effect of growth hormone-releasing factor infusion on somatotropin, prolactin, thyroxine, insulin, insulin-like growth factor I and blood metabolites in control and somatostatin-immunized growing pigs. 167 61

In the present work, somatostatin-like immunoreactivity (SLI) in human milk was characterized. In the early postpartum period, SLI levels were highest on the first day after delivery, and then gradually declined. From the fifth day postpartum, SLI levels in milk seemed unchanged. On the fifth day after delivery, milk SLI was significantly (p less than 0.01) higher than plasma SLI (126.3 +/- 11.7 vs. 17.6 +/- 1.1 pmol/L). The results indicate an active transport from blood or synthesis of somatostatin within the mammary gland. Gel filtration studies of skimmed milk, as well as milk exposed to urea and HCl, and aspirated milk from the human premature newborn, revealed that the main portion of milk SLI either represents somatostatin covalently bound to a larger protein, or more likely, a high molecular weight variant of somatostatin.
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PMID:A characterization of immunoreactive somatostatin in human milk. 196 41

Trauma and injury are associated with accelerated protein loss. Counterregulatory hormones are possible mediators of this response. In the present study, the effect of glucagon and glucagon plus bradykinin on leucine and urea kinetics was examined in nine normal volunteers during somatostatin infusion and basal insulin replacement. Bradykinin was given because of its prostaglandin-stimulating qualities and the potential anabolic action of prostaglandins. Physiological hyperglucagonemia elicited a small but significant reduction of total leucine flux and rate of urea synthesis. Simultaneously, leucine oxidation increased by 70%. The simultaneous infusion of bradykinin did not alter glucagon-related changes in urea or leucine kinetics. Bradykinin, however, significantly attenuated the stimulation of leucine oxidation by glucagon. These results suggest that glucagon and tissue factors are involved in controlling leucine metabolism in humans.
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PMID:Bradykinin attenuates glucagon-induced leucine oxidation in humans. 197 88

The recent study has demonstrated the presence of somatostatin (SRIF) secretory cells in the rat glomerulus. Because of the polyvalent actions of this peptide, SRIF may play some roles in the evolution of chronic renal failure. The present study evaluated the effects of a long acting SRIF analogue, SMS 201-995 on the progression of renal failure in 3/4 nephrectomized (NPX) rats. Animals were divided into four groups; (1) normal control (C) (n = 9), (2) NPX-C (n = 10), (3) NPX treated with SMS 201-995 (0.5 micrograms/day) (NPX-0.5) (n = 9) and (4) NPX with SMS 201-995 (5.0 micrograms/day) (NPX-5.0) (n = 9). This drug was subcutaneously given daily for 6 weeks. Periodic observations were done at 0, 3 and 6 weeks. Both hematocrit and systolic blood pressure showed significant fall and rise, respectively, in NPX rats compared with C at 3 and 6 weeks. Also both serum creatinine and blood urea nitrogen in these groups elevated significantly at 3 and 6 weeks compared with C. Not significant changes were observed in the 24-h urine volume among the NPX rats. At 6 weeks, the urinary protein excretion in NPX-5.0 was significantly less than those in NPX-C and NPX-0.5 rats. Urinary sodium excretion in NPX-5.0 was significantly lower than that in NPX-C. Histologic examination of the kidney showed less proliferation of mesangial cells in NPX-5.0 than NPX-C. These results suggest that SMS 201-995 may limit the rate of progression of chronic renal failure in this experimental model.
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PMID:Effects of chronic administration of somatostatin analogue SMS 201-995 on the progression of chronic renal failure in subtotal nephrectomized rats. 227 32


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