Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q07644 (polypeptide)
 72,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present experiments were carried out to clarify the role of endogenous somatostatin (SRIF) in the regulation of PRL and TSH release. The effects of electrical stimulation of the hypothalamic periventricular nucleus (PE) on vasoactive intestinal polypeptide (VIP)-induced PRL and TRH-stimulated TSH secretion were studied using pentobarbital-anesthetized male rats bearing indwelling cannulae in the right atria. The animals were implanted in the PE with bipolar concentric stimulating electrodes 1 week before the experiments began. The effects of a bolus injection or a continuous infusion of SRIF-14 (iv, 7.6 or 10 nmol/100 g BW, respectively) on the PRL or TSH release induced by VIP or TRH were also examined. Electrical stimulation of the PE significantly enhanced VIP-induced PRL release 19 min after the bolus injection of VIP (from 29.3 +/- 7.2 to 59.7 +/- 14.9 ng/ml, P less than 0.05). A bolus injection of SRIF had a similar effect and increased the PRL response to VIP (from 29.3 +/- 7.2 to 114.7 +/- 22.4 ng/ml, P less than 0.01). Continuous infusion of SRIF did not decrease the stimulatory effect of VIP on PRL release; on the contrary it significantly increased the PRL response to a first VIP injection (10 min after the onset of SRIF-14 infusion) over that observed after a second administration of VIP. Neither electrical stimulation of the PE nor the bolus SRIF-14 injection modified basal PRL secretion. Electrical stimulation of the PE slightly but significantly increased the TSH response to a bolus injection of TRH, but had no effect on the basal TSH release. In contrast, both the bolus injection and the continuous infusion of SRIF-14 significantly and persistently inhibited the TRH-stimulated TSH release. These results suggest that 1) SRIF does not inhibit VIP-induced PRL secretion in vivo but rather enhances it through some unknown mechanism; 2) SRIF inhibits TRH-stimulated TSH secretion.
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PMID:Evidence for a synergistic effect of somatostatin on vasoactive intestinal polypeptide-induced prolactin release in the rat: comparison with its effect on thyrotropin (TSH)-releasing hormone-stimulated TSH release. 288 77

The peroxidase-antiperoxidase immunohistochemical technique has been used to examine the co-existence of peptides within individual neurons of the rat visual cortex. Pairs of consecutive paraffin sections were stained alternately for 2 of the 4 peptides: somatostatin (SRIF), vasoactive intestinal polypeptide (VIP), cholecystokinin (CCK) and neuropeptide Y (NPY). Analysis revealed the co-existence of SRIF with VIP, CCK and NPY and between VIP and CCK. These results show that the co-localization of neuropeptides in cortical neurons is more widespread than previously demonstrated.
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PMID:Extensive co-existence of neuropeptides in the rat visual cortex. 289 Apr 12

By using only reverse-phase h.p.l.c., three fragments of prosomatostatin were isolated from an extract of a human pancreatic neuroendocrine tumour that produced somatostatin, vasoactive intestinal polypeptide and gastrin-releasing peptide. The amino acid composition of the peptides indicated that they represented prosomatostatin-(1-63)-peptide, prosomatostain-(65-76)-peptide and prosomatostatin-(79-92)-peptide (somatostatin-14). The identity of prosomatostatin-(1-63)-peptide was confirmed by characterization of the products of digestion with Armillaria mellea (honey fungus) proteinase. Partial micro-sequencing of prosomatostatin-(1-63)-peptide showed that the Gly24-Ala25 bond of preprosomatostatin was the site of cleavage of the signal peptide. Thus human prosomatostatin is a protein of 92 amino acid residues that is proteolytically cleaved in a pancreatic tumour at the site of a dibasic-residue (arginine-lysine) processing site and at a single-monobasic-residue (arginine) processing site.
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PMID:Characterization of three peptides derived from prosomatostatin [prosomatostatin-(1-63)-, -(65-76)- and -(79-92)-peptides] in a human pancreatic tumour. 289 3

Antibodies against neuropeptides and against a vitamin D-dependent calcium-binding protein (CaBP) label small cells with nonpyramidal-like morphology in the cat visual cortex (areas 17, 18, and 19). Since GABAergic cells are interneurons, a double-staining procedure was used to test for the coexistence of cholecystokinin (CCK), somatostatin (SRIF), neuropeptide Y (NPY), corticotropin-releasing factor (CRF), vasoactive intestinal polypeptide (VIP), and CaBP with glutamic acid decarboxylase (GAD). Our results show that CRF and VIP do not coexist with GAD, while the 3 other peptides and CaBP do. Hence GAD-positive cells can be subdivided into 4 broad groups: (1) cells that are only GAD-positive, (2) cells that are GAD- and CaBP-positive, (3) GAD-positive neurons also containing CCK, and (4) GAD-positive cells that also contain SRIF. A small subset of class 2 also contains SRIF and most cells of class 4 also contain NPY. The 4 classes of GAD-positive cells differ in laminar position: class 1 predominates in layers IV and V, classes 2 and 3 in the upper laminae (II and III), and class 4 in the deepest layer (VI).
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PMID:Heterogeneity of GABAergic cells in cat visual cortex. 289 15

The caudo-cranially intermediate one-third of medullary dorsal region, the periaqueductal grey and the rostro-ventral portion of the midbrain tegmentum of adult chickens were studied in detail by means of the PAP-DAB procedure, to define further the main morphological features of the neuronal populations that in previous studies had shown VIP (Vasoactive Intestinal Polypeptide),-Somatostatin (SRIF)-, and Bombesin-like immunoreactivities. In the medulla, VIP-like immunoreactivity was detected within neuronal bodies and processes and extended down to the cervical spinal cord. SRIF-like immunoreactivity was seen only within nerve cell processes, at least a part of which could be sensitive fibre terminals. Bombesin-like immunoreactivity was observed only within neuronal processes. In the periaqueductal grey, all 3 immunoreactivities were detected within perikarya and neuronal processes, with a higher density cranially. In the rostro-ventral portion of the midbrain tegmentum, VIP-like and Bombesin-like immunoreactivities were detected (the latter being located somewhat more cranially) both in neuronal bodies and in processes. SRIF-like immunoreactivity was found in this region only in long neuronal processes.
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PMID:Medullary and mesencephalic neuronal groups reacting to antibodies against VIP, somatostatin and bombesin in adult Gallus gallus domesticus. 289 35

The immunocytochemical localizations of corticotropin-releasing factor (CRF), somatostatin (SRIF), and vasoactive intestinal polypeptide (VIP) were studied in the human parabrachial nuclei (PBN) using the avidin-biotin complex (ABC) technique. The brains were obtained from seven adult male human subjects of 38-74 years. In three cases, the brains were fixed within 2 hr, in four cases within 5 hr, postmortem. All of these peptides were detected in fibers through the orocaudal extent of the lateral PBN, whereas the medial nucleus contained only CRF immunoreactive fibers. Immunoreactive fibers were distributed unevenly within the lateral nucleus with the highest density in the dorsal and much fewer in the ventral part of the lateral subdivision. The highest to lowest density of immunostained processes were detected using CRF, SRIF, and VIP antisera, respectively. Since NPB is known as an important relay nucleus for the central autonomic pathway, the presence of the above noted neuropeptides in nerve fibers in this area may suggest a neurotransmitter or neuromodulatory role of CRF, somatostatin, and VIP in certain autonomic nervous mechanism of the human brain.
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PMID:Localization of corticotropin-releasing factor, somatostatin, and vasoactive intestinal polypeptide in the parabrachial nuclei of the human brain. 290 94

Intracerebroventricular (icv) injection of alpha-human atrial natriuretic polypeptide (alpha hANP) or alpha-rat ANP (0.6 and 3 nmol/rat) elicited an increase in plasma GH levels both in conscious freely moving rats and in urethane-anesthetized rats when given at the trough of spontaneous GH secretion. Antiserum specific for rat GRF did not affect the plasma GH increase induced by icv injection of alpha hANP. Intracerebroventricular injection of alpha ANP (3 nmol/rat) failed to stimulate GH secretion in conscious rats pretreated with cysteamine (30 mg/100 g BW, sc), a depletor of somatostatin (SRIF), and in conscious rats during constant iv infusion of SRIF (55 ng/ml). GH release induced by iv injection of synthetic rat GRF (200 ng/100 g BW) was exaggerated by alpha hANP (3 nmol/rat, icv) in conscious rats. These results suggest that central ANP stimulates pituitary GH secretion possibly by inhibiting SRIF release from the hypothalamus in the rat.
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PMID:Stimulation of growth hormone secretion by central administration of atrial natriuretic polypeptide in the rat. 296 63

We have studied the concentration of various gastrointestinal peptides in a crude porcine secretin (Boots) preparation and pure natural porcine secretin (GIH, Kabi) preparation. Boots secretin was found to contain 140.3 ng secretin, 1.27 ng human pancreatic polypeptide (hPP), 1.03 ng gastrin, 137.4 ng cholecystokinin (CCK), 241 microU insulin, 1.86 ng vasoactive intestinal polypeptide (VIP), 2.22 ng glucagon and 6.60 ng somatostatin (SRIF) per Crick Harper unit Boots secretin. Sephadex gel filtration demonstrated that the immunoreactivity was due to the hormone per se. GIH secretin contained 240 ng secretin per clinical unit (CU) and less than detectable concentrations of hPP, gastrin, CCK, insulin, VIP, glucagon and SRIF. To determine the clinical significance of having contaminating peptides in Boots secretin, we investigated the effect(s) in 4 subjects. Determined in a highly gastrin-specific assay, the mean plasma gastrin response to Boots secretin administration was slightly, but not significantly greater than the GIH secretin response at 1 and 2.5 minutes. However, in some subjects false positive elevations in plasma gastrin immunoreactivity occurred when some commercially available kit gastrin assays were employed. After intravenous injection of Boots secretin, mean plasma hPP levels rose significantly more than after GIH secretin administration. The mean peak plasma insulin level after GIH secretin administration was significantly higher than after Boots secretin. Neither secretin preparation caused a change in plasma glucose, glucagon and SRIF levels. From these results, it is suggested that GIH secretin be used as the preparation of choice in provocative testing for diagnosing gastrinoma or deficiencies of exocrine pancreatic function.
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PMID:Stimulation of human pancreatic polypeptide and gastrin by Boots and GIH secretin: in vitro and in vivo studies. 355 22

Somatostatin (somatotropin release-inhibiting factor; SRIF) is a tetradecapeptide present in brain, pancreas, gastrointestinal tract, and thyroid that inhibits the secretion or action of several hormones in these tissues. We observed that the toad urinary bladder contains concentrations of endogenous somatostatin (8.0 pg/micrograms of protein) comparable to those found in the mammalian pancreas and gastrointestinal tract. To determine if somatostatin directly alter the action of vasopressinn we studied the effects of this polypeptide on vasopressin-stimulated transport processes in the toad urinary bladder in vitro. Somatostatin produced a dose-dependent, reversible inhibition of vasopressin-stimulated osmotic water flow; it inhibited theophylline-stimulated osmotic water flow but not the water flow stimulated by 8-p-chlorophenylthioadenosine 3',5'-cyclic monophosphate. These data are consistent with an inhibition of both basal and hormone-stimulated adenylate cyclase. Vasopressin-stimulated short circuit current was not inhibited by somatostatin. These studies provide direct evidence for an effect of somatostatin on hormone-modulated epithelial transport in tissues other than the gastrointestinal tract. We propose that endogenous somatostatin may function as a local regulator of the cellular action of vasopressin on osmotic water flow.
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PMID:Somatostatin: an endogenous peptide in the toad urinary bladder inhibits vasopressin-stimulated water flow. 610 10

Peripheral plasma concentrations of gastroenteropancreatic peptides were measured during a 3-h period of bicycle exercise at 40% of maximal oxygen uptake in six normal men. Marked increases (P < 0.02) were found in vasoactive intestinal polypeptide (VIP) [1.8 +/- 0.7 (rest) vs. 22.3 +/- 5.4 pmol x l-1 (mean +/- SE) (3 h)], secretin (0.5 +/- 0.5 vs. 11.1 +/- 2.7 pmol x l-1), pancreatic polypeptide (PP) (4.0 +/- 1.5 vs. 46.3 +/- 11.5 pmol x l-1), somatostatin (SRIF) (12.8 +/- 1.2 vs. 17.7 +/- 0.6 pmol x l-1), whereas no changes occurred in gastric inhibitory polypeptide (37.3 +/- 5.9 vs. 39.2 +/- 9.8 pmol x l-1). Immunoreactive insulin and C-peptide decreased from 0.08 +/- 0.004 and 0.39 +/- 0.03 pmol x l-1, respectively, to 0.04 +/- 0.003 (P < 0.005) and 0.13 +/- 0.02 (P < 0.001). The significant decrease in C-peptide and in the C-peptide-to-insulin molar ratio indicate decreased insulin secretion and clearance, respectively, during exercise. Plasma glucose decreased [5.0 +/- 0.1 (rest) vs. 4.2 +/- 0.3 mmol.l-1 (3 h)] (P < 0.01). During 3 h of rest, none of the measured parameters had changed. The marked exercise-induced changes in plasma concentrations of PP, secretin, VIP, and SRIF are provocative. We know in detail neither the stimuli for the release of these peptides nor their physiological role during exercise.
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PMID:Gastroenteropancreatic hormonal changes during exercise. 610 73


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