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1.
The effect of bombesin on gastrin release and gastric acid secretion was investigated in 10 healthy volunteers. Bombesin (0.6 μg · Kg?1 · hr?1) produced a significantly higher (p< 0.001) increase in plasma gastrin levels (86.7 11.1 pmo/1 than after a protein meal (39.6 ± 5.6 pmol1/1). The gastric acid secretory response to bombesin (12.1 ± 2.9 mEq · hr?1) was however significantly lower (p< 0.005) than the maximal response produced by pentagostrin (20.9 ± 3.5 mEq · hr?1) at the dose of 6 μg · Kg?1. Atropine did not modify gastrin release induced by bombesin but significantly reduced gastric acid secretion (p< 0.01). From the data presented it may be hypothesized that less biologically active forms of gastrin and/or other peptides inhibiting the gastrin effect upon gastric acid secretion may be released by bombesin.  相似文献   

2.
In this study the effect of 10 and 20 μg · kg?1 · h?1 atropine sulfate on release and pancreatic effects of neurotensin was studied in 4 dogs. Neurotensin plasma levels rose significantly when a liquid fat preparation was infused intraduodenally. This rise was almost completely abolished by simultaneous infusion of atropine. Atropine further suppressed basal and fat-stimulated output of pancreatic volume, protein, and bicarbonate; it also reduced pancreatic secretion stimulated by an intravenous infusion of low doses (2.5 to 20 pmol · kg?1 · min?1) neurotensin. The effect of higher doses (80 and 240 pmol · kg?1 · min?1) of neurotensin was less affected.As neurotensin plasma levels in contrast to normal oral feeding did not rise after sham feeding, our findings suggest that release and action of neurotensin may at least in part be dependent on a cholinergic, non-cephalic mechanism.  相似文献   

3.
The dose-dependent effect of intravenously infused synthetic somatostatin-14 on basal and postprandial insulin and gastrin release was assessed in anesthetized rats.Infusion of 1 ng · kg?1 · min?1 elicited a significant reduction of basal and postprandial insulin levels compared to the saline control group. At 15 ng · kg?1 · min?1 basal insulin was not affected but postprandial insulin levels were still significantly reduced. At 30 ng · kg?1 · min?1 neither basal nor stimulated insulin levels were affected. At the highest concentration of 120 ng · kg?1 · min?1 basal and postprandial insulin levels were suppressed similar to the lowest infusion rate of 1 ng · kg?1 · min?1. Basal gastrin levels were significantly reduced only at the highest rate of 120 ng · kg?1 · min?1. A significant reduction of postprandial gastrin levels was observed at 15 ng · kg?1 · min?1 and all higher infusion rates employed. Measurements of plasma somatostatin-like immunoreactivity (SLI) demonstrated that plasma SLI levels during the lowest infusion rate of 1 ng · kg?1 · min?1 were not different from the controls. No significant rise of plasma SLI levels was observed in response to the test meal. The higher infusion rates elicited a dose-dependent increase in plasma SLI levels. These data demonstrate that in rats somatostatin exerts a biological effect on insulin release at very low doses while certain greater infusion rates have no suppressive effect. Gastrin secretion is inhibited in a more linear pattern.  相似文献   

4.
Bombesin, acetylcholine, prostaglandins and somatostatin are all thought to be involved in the regulation of gastrin release and gastric secretion. We have studied the effects of low doses of atropine, 16-16(Me)2-prostaglandin E2 (PGE2) and somatostatin-14 on bombesin-stimulated gastrin release and gastric acid and pepsin secretion in conscious fistula dogs. For reference, synthetic gastrin G-17 was studied with and without somatostatin. Bombesin, in a dose-related manner, increased serum gastrin, which in turn stimulated gastric acid and pepsin secretion in a serum gastrin, concentration-dependent manner. Somatostatin inhibited gastrin release by bombesin as well as the secretory stimulation by G-17; the combination of sequential effects resulted in a marked inhibition of bombesin-stimulated gastric acid and pepsin secretion. PGE2 also strongly inhibited gastrin release and acid and pepsin secretion. Atropine had no significant effect on gastrin release, but greatly inhibited gastric secretion. Thus somatostatin and PGE2 inhibited at two sites, gastrin release and gastrin effects, while atropine affected only the latter.  相似文献   

5.
T Pappas  D Hamel  H Debas  J Walsh  Y Tache 《Peptides》1985,6(5):1001-1003
Spantide ([d-Arg1, d-Trp7,9, Leu11] substance P) was shown to function not only as a substance P receptor antagonist but also as a bombesin receptor antagonist. This study examined the effects of spantide on intravenous bombesin-induced stimulation of gastrin and acid secretion. Dogs were infused with spantide (1 or 10 nmol kg 1 hr 1) or saline and bombesin (60 pmol kg-1 hr-1), and the gastric acid and plasma gastrin responses were monitored. Spantide did not significantly modify gastrin or gastric acid secretion induced by bombesin. It is concluded that spantide may not be a useful bombesin antagonist for in vivo studies.  相似文献   

6.
Bombesin, besides many other actions on the mammalian gastroentero-pancreatic tract, strongly stimulates the release of pancreatic-polypeptide (PP) in dogs. In 8 healthy human volunteers (5 males, 3 females), the PP response during bombesin infusion was low (25.7 ± 6.3 peak vs. 5.0 ± 2.0 basal pmol/1) compared to the effect of a protein meal (144.1 ± 13.4 pmol/1) or to the gastrin response to the same dose of the amphibian polypeptide (140.0 ± 23.6 pmol/1 eq SHG 17 I). The response pattern of PP and gastrin was different as PP concentrations peaked 10 min after cessation of bombesin infusion (32.0 ± 4.9 pmol/1) when gastrin concentrations already were down to one third of the maximal response. Atropine inhibited the PP response to bombesin but did not abolish it completely. It is concluded that in man, the total effect of bombesin on PP secretion is minor compared both to the effect of the peptide on gastrin secretion in man and to the effect of bombesin in dogs. It is suggested that bombesin might have a dual, inhibitory-stimulatory, effect on PP secretion in man.  相似文献   

7.
Human gastrin-releasing peptide: biological potency in humans.   总被引:3,自引:0,他引:3  
Gastrin-releasing peptide (GRP) was infused in graded doses (1-27 pmol/kg per h) to healthy human volunteers to study the effects on gastric, pancreatic and gallbladder functions as well as on gastrin, CCK and PP release. The results were compared to equimolar doses of synthetic bombesin. GRP significantly (P less than 0.05) stimulated gastric and pancreatic secretory responses, gallbladder contraction and gastro-enteropancreatic hormone release in a dose-dependent manner. GRP was found to be equipotent to bombesin with respect to gastric acid secretion, pancreatic enzyme output, gallbladder contraction and plasma hormone release. We conclude (a) that human GRP has similar biologic effects as synthetic bombesin; (b) as GRP is localized exclusively in nerve tissue and has potent effects on different organs, it is a likely candidate for peptidergic control of human gastric, pancreatic and gallbladder functions.  相似文献   

8.
《Regulatory peptides》1987,17(5):285-293
Infusion of the neuropeptide bombesin stimulates the secretion of several gastrointestinal hormones by an unknown mechanism. We have investigated the effects of atropine (15 ng/kg as bolus followed by 2.5 ng/kg · 30 min) and somatostatin (125 μg as i.v. bolus followed by 62.5 μg/30 min) on the stimulation of 3 hormones (gastrin, cholecystokinin and pancreatic polypeptide) by 60 pmol/kg · 20 min bombesin in 6 healthy volunteers. Plasma samples for measurement of hormones by sensitive and specific radioimmunoassays were obtained at − 5, 0, 2.5, 5, 7.5, 10, 15, 20, 25 and 30 min. Bombesin induced significant increases in plasma gastrin (12 ± 2 to 34 ± 3 pM; P < 0.0005), cholecystokinin (1.2 ± 0.2 to 8.9 ± 0.7 pM; P < 0.0001) and pancreatic polypeptide (22 ± 4 to 72 ± 19 pM; P < 0.05). There were great differences between the effects of atropine and somatostatin on the hormonal responses to bombesin. Atropine slightly increased the response of gastrin by 19% and that of cholecystokinin by 15%, but strongly inhibited the bombesin-stimulated pancreatic polypeptide secretion by 97%. On the other hand, somatostatin inhibited the bombesin-induced secretion of gastrin by 48%, cholecystokinin by 82% and pancreatic polypeptide by 107%. These results point to considerable qualitative and quantitative differences in the stimulatory mechanisms of bombesin on the hormones studied.  相似文献   

9.
The optimization task was performed using the gluconic acid synthesis by the Acetobacter methanolicusMB 58 strain. The microorganisms were grown continuously on methanol as the growth substrate. After finishing the growth process by the deficiency of N and P, the gluconic acid synthesis was started by adding glucose. The synthesis process was performed continuously. The oxygen transfer rate depended on the gluconic acid concentration. During the growth process, the oxygen transfer rate reached a value of about 13 g O2 · kg?1 · h?1using a 30-l glass fermenter equipped with a 6 blade stirrer and fully baffled. This rate declined to a value of between 2 and 5 g O2 · kg?1 · h?1 in the presence of gluconic acid concentrations above 150 g gluconic acid · kg?1medium. The yield (g gluconic acid · g?1glucose) depended on the gluconic acid concentration and amounted to y = 0.7 in relation to 150 g gluconic acid · kg?1medium and y = 0.8 in relation to 200 g · kg?1medium, respectively. The fermenters were coupled with ultrafiltration moduls (Fa. ROMICON and Fa. SARTORIUS). The biomass concentrations amounted from 5 to 40 g dry mass kg?1medium. The ultrafiltration modules retained the biomass within the fermentation system. A glucose solution (30 to 50 weight percent glucose) was continuously dosed into the fermenter. The retention time was chosen between 2 and 30 h. The gluconic acid synthesis rate reached values of up to 32 g gluconic acid · kg?1 · h?1. Within a range of up to 250 g gluconic acid · kg?1medium, the acid concentration had no influence on the enzyme activity.  相似文献   

10.
Measurements of bimodal oxygen uptake have been made in a freshwater air-breathing fish,Notopterus chitala at 29.0±1(S.D.)°C. xhe mean oxygen uptake from continuously flowing water without any access to air, was found to be 3.58±0.37 (S.E.) ml O2 · h?1 and 56.84+4.29 (S.E.) ml O2 · kg?1 · h?1 for a fish weighing 66.92 + 11.27 (S.E.) g body weight. In still water with access to air, the mean oxygen uptake through the gills were recorded to be 2.49 ± 0.31 (S.E.) ml O2 · h?1 and 38.78 ± 1.92 (S.E.) ml O2 · kg?1 · h?1 and through the accessory respiratory organs (swim-bladder) 6.04±0.87 (S.E.) ml O2 · h?1 and 92.32±2.91 (S.E.) ml O2 · kg?1 · h?1 for a fish averaging 66.92±11.27 (S.E.) g. Out of the total oxygen uptake (131.10 ml O2 · kg?1 · h?1), about 70% was obtained through the aerial route and the remainder 30% through the gills.  相似文献   

11.
Medullary sites of action for bombesin-induced inhibition of gastric acid secretion were investigated in urethane-anesthetized rats with gastric fistula. Unilateral microinjection of bombesin or vehicle into the dorsal vagal complex was performed using a glass micropipet and pressure ejection of 100 nl volume; gastric acid output was measured every 10 min by flushing the stomach. Microinjection of vehicle into the dorsal vagal complex did not alter gastric acid secretion (1.9 +/- mumol/10) from preinjection levels (2.9 +/- 0.8 mumol/10 min). Microinjection of the stable thyrotropin-releasing hormone (TRH) analog, RX 77368, at a 77 pmol dose into the dorsal vagal complex stimulated gastric acid secretion for 100 min with a peak response at 40 min (24.1 +/- 3.2 mumol/10 min). Concomitant microinjection of RX 77368 (77 pmol) with bombesin (0.6-6.2 pmol) into the dorsal vagal complex dose dependently inhibited by 35-86% the gastric acid response to the TRH analog. Bombesin (6.2 pmol) microinjected into the dorsal vagal complex inhibited by 17% pentagastrin infusion-induced stimulation of gastric acid secretion (13.2 +/- 0.8 mumol/10 min) whereas intracisternal injection induced a 69% inhibition of the pentagastrin response. These results demonstrate that the dorsal motor complex is a sensitive site of action for bombesin-induced inhibition of vagally stimulated gastric secretion. However, other medullary sites must be involved in mediating the inhibitory effect of intracisternal bombesin on pentagastrin-stimulated gastric acid secretion.  相似文献   

12.
Temporal coordination between duodenal migrating myoelectric complexes (MMC) and pancreatic exocrine secretion, and the effects of porcine peptide YY (PYY) on gastroduodenal motility and pancreatic exocrine secretion were examined during the interdigestive period in conscious mature sheep. Fluid and enzyme secretions from the exocrine pancreas showed a periodic pattern corresponding to the phases of duodenal MMC, although these secretion rates were maintained at a high level during phase II in sheep. Intravenous continuous infusion of PYY at doses ranging from 50 to 200 pmol · kg−1 · h−1 or intravenous bolus infusion of PYY at doses ranging from 50 to 200 pmol · kg−1 showed a tendency to prolong the first cycle of the duodenal MMC and significantly shorten the second cycle. However, there was almost no effect on ruminal contractions from the PYY administration. In the pancreatic exocrine secretion, PYY could inhibit only bicarbonate secretion at only the highest dose of 200 pmol · kg−1. These results imply that endogenous PYY may play a physiological role in the regulation of the duodenal MMC cycles in sheep but not in ruminal contractions. PYY seems unlikely to regulate the pancreatic exocrine secretion in normal sheep, because a supraphysiological dose of PYY was required to inhibit the pancreatic exocrine secretion. Accepted: 3 March 1997  相似文献   

13.
The effects of intravenous infusion of neurotensin on small bowel motility was studied in conscious rats. During 1 h a standardized test meal of glucose, polyethyleneglycol (PEG) 3000, phenol red and 125I-labelled polyvinylpyrrolidone was administered via a permanent gastric catheter and simultaneously the bile-excreted radiopharmaceutic 99Tcm-Solco-HIDA was infused intravenously. Immediately after the infusions the gastrointestinal specimen was excised and examined for distribution of radioactivity. Both doses of neurotensin (0.1 and 0.3 μg · kg?1 · h?1) resulted in an increase in the neurotensin-like immunoreactivity (NTLI) of plasma to levels similar to that found after a fatty meal. Concurrently the small bowel transport pattern was changed from an interdigestive state to one similar to that found after a meal. In animals not receiving the gastric test meal, neurotensin (0.1–0.5 μg · kg?1 · h?) had no effect on motility. Infusion of the gastric test meal alone did not change the interdigestive motility or the NTLI value. This indicates that the presence of gastric infusates potentiates the effect of neurotensin on small bowel motility. The motility response to neurotensin did not differ between intact and vagotomized animals. This contrasts to earlier findings that the small bowel motility response to a fatty meal is dependent on intact vagal function. Thus, a difference in the mechanism responsible for the motility responses between a fatty meal and neurotensin exists. In view of this finding it seems reasonable to assume that neurotensin cannot be the only factor responsible for the shift in motility found after a fatty meal.  相似文献   

14.
The presence of adenylate cyclase (ATP pyrophosphate-lyase (cyclizing) EC 4.6.1.1) activity was demonstrated in human erythrocyte ghosts and was found to be around 3 pmol adenosine ′,5′-monophosphatase (cyclic AMP) · 2 h?1 · mg?1 protein. This enzymatic activity is strongly stimulated by NaF and 5′-guanylimidodiphosphate, is slightly stimulated by epinephrine, norephrine, soproterenol, and prostaglandin E, and is inhibited by calcium. The hormone stimulation is not potentiated by 5′-guanylylimidodiphosphate.  相似文献   

15.
Telemetered heart rate (fH) was examined as an indicator of activity and oxygen consumption rate (VO2) in adult, cultivated, Atlantic salmon, Salmo salar L. Heart rate was measured during sustained swimming in a flume for six fish at 10° C [mean weight, 1114 g; mean fork length (f. l.), 50·6 cm] and seven fish at 15° C (mean weight, 1119 g; mean f. l., 50·7 cm) at speeds of up to 2·2 body lengths/s. Semi–logarithmic relationships between heart rate and swimming speed were obtained at both temperatures. Spontaneously swimming fish in still water exhibited characteristic heart rate increases associated with activity. Heart rate and Vo2 were monitored simultaneously in a 575–1 circular respirometer for six fish (three male, three female) at 4° C (mean weight, 1804 g; mean F. L., 62· cm) and six fish (three male, three female) at 10° C (mean weight, 2045 g; mean f. l., 63·2 cm) during spontaneous but unquantified activity. Linear regressions were obtained by transforming data for both fH and Vo2 to log values. At each temperature, slopes of the regressions between fH and Vo2 for individual fishes were not significantly different, but in some cases elevations were. All differences in elevation were between male and female fish. There were no significant differences in regression slope or elevation for fish of the same sex at the two temperatures and so regressions were calculated for the sexes, pooling data from 4 and 10° C. There was no significant difference in the mean ± S. D. Vo2 between the sexes at 4° C (male, 66·0 ± 59·6 mgO2 kg?1 h?1; female, 88·0 ± 60·1 mgO2 kg?1 h?1) or 10° C (male, 166·2 ± 115·4 mgO2 kg?1 h?1; female, 169·2 ± 111–1 mgO2 kg?1h?1). Resting Vo2 (x?± s. d.) at 4°C was 36·7 ± 8.4 mgO2 kg?1 h?1, and 10° C was 72·8 ± 11·9 mgO2 kg?1 h?1. Maximum Vo2 (x?± S. D.) at 4° C was 250·6 ± 40·2 mgO2 kg?1 h?1, and at 10° C was 423·6 ± 25·2 mgO2 kg?1 h?1. Heart rate appears to be a useful indicator of metabolic rate over the temperature range examined, for the cultivated fish studied, but it is possible that the relationship for wild fish may differ.  相似文献   

16.
The effect of intravenously administered calcitonin and secretin on bombesin-stimulated serum gastrin and gastric acid secretion was studied in 7 volunteers. Secretin G.I.H. (1 C.U./kg per h) and calcitonin (0.5 I.U./kg per h) significantly (P < 0.05) inhibited the serum gastrin and gastric acid responses to bombesin-14 (90 pmol/kg per h). Inhibition of gastrin release could not fully account for the inhibition of gastric acid secretion.  相似文献   

17.
Two analogues of somatostatin (d-Trp8,d-Cys14-somatostatin, and the octapeptide DesAA1,2,3,4,13,14,d-Trp8,GABA12-somatostatin) were compared with somatostatin using infusions, of 0.1 and 0.5 μg · kg?1 · min?1 in conscious dogs. Basal concentrations of insulin and glucagon were markedly and similarly lowered by all three somatostatin (SRIF) compounds at either dose. Arginine stimulation of insulin and glucagon secretion was entirely abolished by SRIF and by the octapeptide during infusion at 0.1 μg · kg?1 · min?1 but both hormones were only partly inhibited by d-Trp8,d-Cys14-SRIF. The higher dose (0.5 μg · kg?1 · min?1) of all three SRIF peptides lowered plasma insulin and glucagon before and during arginine stimulation. The recovery of plasma insulin and glucagon was delayed after discontinuation of the d-Trp8,d-Cys14-SRIF, and particularly after the octapeptide when compared with SRIF suggesting a longer duration of action of the analogues.The results did not confirm the previously suggested selective suppression of glucagon by d-Trp8,d-Cys14-SRIF. The new octapeptide appears to be promising for future clinical studies due to its potent inhibitory effect on insulin and glucagon, and its prolonged duration of action.  相似文献   

18.
The effect of porcine gastrin releasing peptide (GRP), a heptacosapeptide with potent gastrin releasing activity which has recently been isolated from porcine non-antral gastric tissue, on pituitary function was investigated in the rat. Graded doses of synthetic porcine GRP were injected intravenously and the animals were killed at various intervals after injection. Growth hormones, LH, FSH, and TSH were measured in serum by specific radioimmunoassays. GRP had no significant effect on growth hormone or FSH serum concentrations at any dose or sampling time studied. In contrast, the heptacosapeptide significantly stimulated LH and suppressed TSH secretion in a dose-related fashion. Since there are striking structural similarities between GRP and bombesin, a tetradecapeptide from amphibian skin which shows amino acid homology with the C-terminal region of GRP, GRP may be the mammalian counterpart of bombesin.  相似文献   

19.
M. Parry  B.V. Heathcote 《Life sciences》1982,31(14):1465-1471
The ability of pirenzepine and atropine, given i.v., to inhibit gastric acid and salivary secretion and increase pupil diameter has been assessed in the rat. Pirenzepine had a similar potency against acid secretion, ED50 0.71 (0.41 to 1.1) mg.kg?1, and salivary secretion, ED50 0.50 (0.43 to 0.59) mg.kg?1, whilst its potency was less in the eye, ED50 1.8 (1.6 to 2.1) mg.kg?1. Astropine however, was more potent in reducing salivary secretion, ED50 0.012 (0.010 to 0.016) mg.kg?1, and increasing pupil diameter, ED50 0.028 (0.025 to 0.031) mg.kg?1 than in inhibiting gastric acid secretion, ED50 0.056 (0.037 to 0.083) mg.kg?1. Therefore, that quantity of pirenzepine which inhibits gastric acid secretion by 50% will have only a slight effect on the eye and will inhibit salivary secretion by a similar magnitude. In contrast, the amount of atropine required to inhibit acid secretion by 50% will significantly increase pupil diameter and abolish salivary secretion.  相似文献   

20.
Neurotensin is a tridacapeptide which has been isolated from bovine hypothalamus. The action of synthetic neurotensin was studied on gastric acid secretion in dogs provided with gastric pouches. Intravenously infused neurotensin, 50 ng × kg?1 × min?1, was found to produce a considerable inhibition of pentagastrin stimulated gastric acid secretion. On the other hand, there was no sign of inhibition of histamine induced gastric acid secretion. The experiments show that neurotensin, isolated from the central nervous system is a potent gastric secretory inhibitor and that it has a selective action in inhibiting gastric acid responses to pentagastrin but not to histamine.  相似文献   

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