Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The responses of pancreatic volume flow and bicarbonate output to intravenous vasoactive intestinal peptide (VIP, 0.8 to 3.2 microgram per kg per hr) and synthetic secretin (32.2 to 129 ng per kg per hr) were compared intraindividually in 5 healthy volunteers. Pure pancreatic juice was obtained by endoscopic cannulation of the main pancreatic duct. The mean +/- SEM observed maximal response of secretin-stimulated juice flow was 248 +/- 7 microliter per kg per 5 min, whereas the observed maximal response for VIP-evoked juice flow was 48 +/- 6 microliter per kg per 5 min. The observed maximal secretin-induced bicarbonate output was 30 +/- 2 muEq per kg per 5 min, and the maximal VIP-related response was 4.3 +/- 0.9 muEq per kg per 5 min. In addition to low efficacy, high dose requirements, and side effects (significant rise in pulse rate and cutaneous flushing at 3.2 micrograms per kg per hr) argue against a major physiological role of VIP as a hormonal stimulant of human pancreatic bicarbonate secretion.
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PMID:Vasoactive intestinal peptide: a secretin-like partial agonist for pancreatic secretion in man. 89 45

Endothelin-1 (ET-1) has been reported to possess a wide variety of biological activities, including neurotransmission. Our aim was to demonstrate ET-like immunoreactivity (ET-LI) and its binding sites in human enteric nervous system using immunohistochemistry and in vitro autoradiography. ET-LI was displayed in nerve bundles and most of the ganglion cells in both myenteric and submucous plexuses, many of which costored VIP. [125I]ET-1 binding sites were identified, especially to plexuses, mucosa, and blood vessels. High-affinity (Kd = 0.35 +/- 0.014 nM; mean +/- SEM) binding sites, with a maximum binding capacity (Bmax) of 92 +/- 6.3 amol/mm2, were demonstrated in the myenteric plexus. This study provides evidence that ET-1 is a neuropeptide in the human colon with binding sites on neural plexuses and mucosa, indicating a possible role in the modulation of motility and secretion in the human intestine.
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PMID:Localization of endothelin-1 and its binding sites to the nervous system of the human colon. 172 11

We investigated the effect of surgical castration of male rats on the binding of [Tyr(125I)10]VIP to receptors on the anterior pituitary gland, superior mesenteric artery, brain, liver, and prostate gland. In anterior pituitary membranes the maximum number of VIP binding sites was increased whereas binding affinity was decreased 24 hours following castration. In particular, the high affinity equilibrium dissociation constant (KD) increased from 0.13 +/- 0.02 nM (mean +/- SEM) to 0.67 +/- 0.07 nM and the maximum number of high affinity binding sites (Bmax) increased from 71 +/- 9 to 470 +/- 112 fmol/mg protein. No significant change was observed in the other tissues. Anesthesia or sham operation did not alter the anterior pituitary VIP receptor binding parameters. The changes in the VIP receptor 24 hours after castration were prevented by prior injection of testosterone. These findings demonstrate tissue-selective alterations to the anterior pituitary VIP receptor by castration that are likely mediated by withdrawal of testosterone.
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PMID:Selective effect of castration on the anterior pituitary VIP receptor of male rats. 196 30

Galanin, a newly discovered peptide, was found throughout the gastrointestinal tract of man, pig, and rat, exclusively in nerves. The concentrations of immunoreactive galanin ranged from 3.7 +/- 0.7 (mean +/- SEM) pmol/g in rat antrum to 76.5 +/- 14.3 pmol/g in pig colon. The predominantly intrinsic origin of the galanin nerves was shown by the finding of the peptide in submucosal ganglion cells, the majority of which also contained VIP. Furthermore, neither extrinsic denervation of the gut nor administration of capsaicin, which selectively destroys extrinsic afferent fibres, had any significant effect on the galanin innervation. The caudal projection of galanin-immunoreactive fibres was demonstrated by complete transection of the gut, which led to their reduction in the 1 to 2 cm distal to the cut. The abundance of galanin in the innervation of the mammalian gut and its reported action on smooth muscle contractility suggest this peptide to be a novel regulatory factor in the control of bowel function.
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PMID:Occurrence and distribution of a newly discovered peptide, galanin, in the mammalian enteric nervous system. 242 61

We previously reported that systemic administration of the recently described GRF peptide antagonist (N-Ac-Tyr1,D-Arg2)GRF-(1-29)-NH2 to adult male rats would suppress the pulsatile release of GH. In the present study, we have sought to determine whether this same antagonist would be efficacious in immature male rats to block spontaneous GH secretion and, as a result, retard several parameters of somatic growth. Indwelling Silastic catheters were placed into the jugular veins of immature male rats (120-140 g) at 29 days of age. After a recovery period of 48 h, beginning at 1000 h, 100-400 micrograms/kg GRF antagonist or its vehicle (controls) were injected iv immediately after withdrawing an initial blood sample from conscious undisturbed animals. Subsequent samples were obtained every 20 min until 1520 h. Red blood cells were resuspended in a restorative volume of saline and reinjected after each blood sample. Results showed that both doses of antagonist prevented the two major periods of episodic GH release observed in controls. For example, mean plasma GH (+/- SEM; nanograms per ml) at 1120 h was 9.0 +/- 2.7 in antagonist-treated rats and 37.1 +/- 5.1 in controls (P less than 0.05). Mean plasma GH (+/- SEM) at 1340 h was 10.8 +/- 3.7 in antagonist-treated rats and 38.8 +/- 9.6 in controls (P less than 0.05). Injection of 400 micrograms/kg of the structurally related VIP antagonist (N-Ac-Tyr1,D-Phe2)GRF-(1-29)-NH2, iv failed to suppress spontaneous GH release. GRF antagonist (100 micrograms/kg) was next administered twice daily iv for 4 days to 31-day-old rats in metabolic cages. This treatment essentially arrested the normal rapid body weight gain, significantly suppressed increases in body and tail lengths, and reduced increases in heart and kidney weights (P less than 0.01). Food intake and fecal output were unchanged by antagonist treatment and, therefore, did not contribute to the observed effects. These results support the idea that a number of tissues and organs are stimulated by the pulsatile secretion of GH and that a peptidic GRF receptor antagonist is useful in blocking episodic GH release in immature animals. As a consequence, this specific antagonist is effective in suppressing numerous aspects of somatic growth.
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PMID:Inhibition of pulsatile growth hormone (GH) secretion and somatic growth in immature rats with a synthetic GH-releasing factor antagonist. 249 21

The retinal pigment epithelium (RPE) from the chick embryo was cultured on permeable support. Using confluent cultures and analysis of the incubation medium, the present study demonstrates that RPE cells cultured on permeable membrane retain functional polarity, a characteristic of the RPE in vivo. The degree of intercellular permeability in the confluent RPE cultures was estimated by following [3H]inulin movement from the apical side to the basal side of the cultures. Twenty-four hours after exposure of the apical side of the culture to [3H]inulin, the 3H concentration in the apical medium remained at 3.4 to 4.4 times of that in the basal medium. The barrier function of RPE disappears in the presence of EDTA. Net unidirectional fluid movement from the apical side of the cultures to the basal side of the cultures is regularly observed in confluent RPE cultures. The rate varies among different preparations of cultures and the highest is 1.60-1.84 microliters/cm2/h. When cultures are given 26 h of [35S]methionine, more than 20 bands with molecular weights ranging from 20,000 to greater than 250,000 Da can be detected in the medium as assessed by autoradiography of SDS-polyacrylamide gels. While six macromolecules appear to be equally concentrated in the basal medium and the apical medium, the majority are in higher concentration in the basal medium. Analysis of the 10% TCA-precipitable fraction of the medium showed that the specific activities in the apical medium and basal medium were 24.0 +/- 0.4 X 10(6) and 46.4 +/- 0.2 X 10(6) (mean +/- SEM, N = 8) cpm/ml/mg RPE protein, respectively. When cultures react with VIP (vasoactive intestinal peptide), the elevated intracellular cyclic AMP is extruded into the medium bathing the cells. However, the rate of extrusion into the basal medium is twice as fast as that into the apical medium. Electron microscopy of the confluent RPE cultures shows morphological polarization of the cells. The intercellular spaces appear to be closed at the apical side of the cells by junctional complexes consisting of tight junctions, zonular adherens junctions, and gap junctions.
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PMID:The chick retinal pigment epithelium grown on permeable support demonstrates functional polarity. 253 34

Advances in immunosuppressive therapy have renewed interest in small bowel transplantation. Little is known, however, about the functional capacity of transplanted intestine. To clarify the potential for normal function, we investigated whether elements of the enteric nervous system are preserved after denervation in our rat model of intestinal transplantation. We investigated whether VIP, a major peptide neurotransmitter of the enteric nervous system, and its receptors are preserved in the bowel after transplantation. In our model of transplantation, avascular fetal jejunum from term Fisher rats is transplanted to the subcutaneous tissues of host syngeneic rats. This "neogut" becomes vascularized and develops characteristics of native small bowel. VIP content was measured by RIA and the in situ distribution of VIP receptors was determined by the technique of receptor autoradiography. Neogut was studied 1 and 3 weeks after transplantation and compared with age-matched rat pup jejunum. Autoradiographs showed high silver grain density, representing VIP binding sites, in the mucosal layers of all tissues studied. VIP content in the transplanted bowel was comparable to that of native gut and showed a rise with developmental age similar to that of native gut. VIP levels (pmole/mg protein, x +/- SEM) were neogut 1 week, 0.26 +/- 0.14; jejunum 1 week, 0.25 +/- 0.07; neogut 3 weeks, 0.60 +/- 0.21; and jejunum 3 weeks, 0.69 +/- 0.16. These results show that VIP receptors and content are preserved in this model of transplantation. This suggests that the enteric nervous system and receptors for peptide neurotransmitters remain intact after transplantation and may retain the potential for regulatory function.
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PMID:VIP receptors and content after bowel transplantation. 254 Dec 80

VIP receptors on blood mononuclear leucocytes and plasma VIP concentrations were studied during a ranger training course lasting for five days with almost continuous physical activity, and energy deficiency. The maximum binding capacity (Bmax) for the high affinity receptor increased (p less than 0.0005) from 0.71 (SEM = 0.11, N = 10) fmol/million cells to a maximum of 7.33 (SEM = 1.0) fmol/million cells on Day 4. There was no significant change in the dissociation constant (Kd) for the high affinity receptor, and no effect on Kd nor Bmax for the low affinity VIP receptor was detected. Plasma VIP concentration increased (p less than 0.0005) from 8.8 pmol/l (SEM = 0.6) to a maximum of 23.4 (SEM = 1.9) on the second day of the course. However, the highest plasma concentrations were about one order of magnitude lower than the dissociation constant (Kd) for the high affinity VIP receptor on the mononuclear leucocytes. These data indicate that heterologous upregulation of the high affinity VIP receptor on mononuclear blood cells takes place during combined strenuous physical exercise, and calorie deficiency.
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PMID:Receptors for vasoactive intestinal peptide (VIP) on human mononuclear leucocytes are upregulated during prolonged strain and energy deficiency. 283

There is little information about the effect of peptides on the VIPergic system. Reports of the influence of secretin and cholecystokinin (CCK) on pancreatic alpha cells are contradictory. With the help of volunteers we investigated the influence of a new synthetic secretin (1 CU/kg/h, 0 to 120 min) alone and in combination with GIH-CCK (1 IU/kg/h, 60 to 120 min) on the concentrations of VIP (n = 13), pancreatic glucagon (PG) (n = 15) and blood sugar (n = 10). 6 of the volunteers were subjected to a randomized cross-over NaCl infusion study. Neither secretin (0 to 60 min) nor secretin and CCK (60 to 120 min) infusion caused a significant change in VIP (31 +/- 3 vs. 34 +/- 4.5 pg/ml, mean +/- SEM, p greater than 0.05), PG (102 +/- 9 vs. 116 +/- 12 vs. 114 +/- 12 pg/ml, p greater than 0.05) or blood sugar (about 90 mg/dl) concentrations. There is no evidence of an influence of secretin and CCK on te VIPergic system and the pancreatic alpha cells.
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PMID:[Absence of effect of secretin and cholecystokinin on plasma concentrations of vasoactive intestinal polypeptide and pancreatic glucagon]. 390 35

The concentrations and hormonal forms of CCK and VIP have been determined in extracts of the brain and duodenum of the developing and adult pig. In methanol extracts of the brain cortex, the single hormone form, CCK8, increased from 130 +/- 20 (Mean +/- SEM) pmol/g at birth to an adult level of 300 +/- 50 pmol/g. In acid extracts of brain, the predominant immunoreactive form had N-terminal immunoreactivity and increased from 240 +/- 20 pmol/g at birth to an adult level 490 +/- 30 pmol/g; the C-terminal immunoreactivity was about 10-fold lower. The concentrations and hormonal forms of immunoreactive CCK in duodenal extracts did not appear to be age-related. C-terminal immunoreactivity in methanol extracts averaged 140 +/- 20 pmol/g and in acid extracts 240 +/- 60 pmol/g. The concentration of N-terminal immunoreactivity in acid extracts averaged 490 +/- 70 pmol/g. The VIP concentrations in acid extracts of the brain cortex was 13.5 +/- 2 pmol/g at birth and rose gradually to 30 +/- 9 pmol/g in the adult; in duodenal extracts it was 240 +/- 18 pmol/g at birth and 195 +/- 38 pmol/g in the adult. These results are in marked contrast with the ontogeny of these hormones in the rat in which brain concentrations of CCK and VIP in the neonate are less than 10% of adult levels and in which there are age-related changes in the content of these hormones in the duodenum as well.
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PMID:Ontogeny of immunoreactive CCK and VIP in pig brain and gut. 608 47


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