Secretin-stimulated Bile Research Articles

Prolonged administration of secretin to normal rats increases biliary proliferation and secretin-induced ductal secretory activity.

Cholangiocyte proliferation is coordinately regulated by a number of gastrointestinal hormones/peptides, some of which display stimulatory effects and some have inhibitory actions on cholangiocyte proliferation. Enhanced biliary proliferation [for example after bile duct ligation (BDL) and partial hepatectomy] is associated with increased expression of secretin receptor (SR), cystic fibrosis transmembrane conductance regulator (CFTR) and Cl(-)/HCO3 (-) anion exchanger 2 and secretin-stimulated ductal secretion, whereas loss/damage of bile ducts [for example after acute carbon tetrachloride (CCl4) administration] is associated with reduced secretin-stimulated ductal secretory activity. There is growing information regarding the role of gastrointestinal hormones the regulation of biliary growth. For example, while gastrin, somatostatin and serotonin inhibit bile duct hyperplasia of cholestatic rats by downregulation of cAMP signaling, secretin has been shown to stimulate the proliferation of normal mice by activation of cyclic adenosine 3',5'-monophosphate (cAMP)-dependent signaling. However, no information exists regarding the stimulatory effects of secretin on biliary proliferation of normal rats. Thus, we evaluated the in vivo and in vitro effect of secretin on biliary proliferation, the expression of markers key of ductal secretion and secretin-stimulated ductal secretion. Normal male rats were treated with saline or secretin (2.5 nmoles/kg BW/day by osmotic minipumps for one week). We evaluated: (I) intrahepatic bile duct mass (IBDM) in liver sections and PCNA expression in purified cholangiocytes; (II) SR and CFTR mRNA expression and secretin-stimulated cAMP levels in purified cholangiocytes; and (III) secretin-stimulated bile and bicarbonate secretion in bile fistula rats. In vitro, normal rat intrahepatic cholangiocyte lines (NRIC) were treated with BSA (basal) or secretin (100 nM) for 24 to 72 hours in the absence/presence of a PKA or a MEK inhibitor before evaluating proliferation by MTS assays. Prolonged administration of secretin to normal rats increased IBDM and PCNA expression in purified cholangiocytes compared to saline-treated normal rats. Also, secretin increased the expression of proteins (SR and CFTR) that are key in the regulating ductal secretion and enhanced secretin-stimulated cAMP levels and bile and bicarbonate secretion. In vitro, secretin increased the proliferation of NRIC, increase that was prevented by PKA and MAPK inhibitors. We have demonstrated that secretin stimulates both in vivo and in vitro biliary proliferation and secretin-stimulated ductal secretory activity in normal rats. We suggest that the stimulatory effect of secretin on biliary proliferation and secretion may be important for preventing biliary dysfunction during ductopenic disorders.

Taurocholate Feeding to Bile Duct Ligated Rats Prevents Caffeic Acid-Induced Bile Duct Damage by Changes in Cholangiocyte VEGF Expression

Cholangiocytes are the target cells in cholestatic models of ductal hyperplasia including bile duct ligation (BDL). We have shown that: (i) cholangiocytes express VEGFR-2 and VEGFR-3; (ii) VEGF-A and VEGF-C stimulate cholangiocyte proliferation via an autocrine mechanism; and (iii) chronic administration of VEGF-A prevents cholangiocyte damage induced by hepatic artery ligation. Caffeic acid phenethyl ester (CAPE) induces growth inhibition in different cells. Taurocholic acid (TC) protects cholangiocytes against injury induced by parasympathetic or sympathetic denervation. The aims of this study were to determine if: (i) CAPE induces bile duct damage; and (ii) TC prevents CAPE-induced bile duct damage by increasing cholangiocyte VEGF expression. Normal and BDL rats (immediately after surgery) were fed 1% TC or control diet in the absence/presence of daily IP injections of CAPE (10 mg/Kg BW). One week later, we evaluated: (i) cholangiocyte apoptosis, proliferation and ductal mass in liver sections; (ii) functional activity by measuring secretin-stimulated bile and bicarbonate secretion; and (iii) VEGF-A/C and VEGFR-2/R-3 expression in liver sections. In vitro, BDL cholangiocytes were exposed to CAPE (40 microM) in the absence/presence of TC (40 microM) with and without pretreatment with VEGF receptor inhibitors before evaluating cholangiocyte apoptosis and proliferation. Chronic CAPE administration to BDL rats increased cholangiocyte apoptosis and decreased ductal mass. This effect was associated with reduced expression of VEGF-A, VEGF-C, VEGFR-2 and VEGFR-3. In vivo, TC feeding partly prevented CAPE-induced changes in cholangiocyte apoptosis and growth and loss of ductal secretion. The protective effect of TC was associated with enhanced VEGF-A, VEGF-C, VEGFR-2 and VEGFR-3. In vitro, TC partially prevented CAPE-induced increases in apoptosis and decreases in cholangiocyte proliferation. These changes were reversed by pretreatment with VEGF-receptor inhibitors. Manipulation of cholangiocyte VEGF expression by bile acids may be important in preventing the impairment of cholangiocyte proliferation by exogenous agents.

The role of opioid peptides in the regulation of secretin-stimulated bile secretion

Influence of intraperitoneal dalargin (dand m-opioid agonist), DADLE (d-opioid agonist), DAGO (m-opioid agonist) and U50488 (k-opioid agonist) on bile secretion which is stimulated by secretin was studied in sharp experiments on white rats. All opioids studied is demonstrated to suppress secretory response of liver upon secretin in different extent. We suppose that opioidergic regulation system has different effect on bile secretion in dependence of baseline level of physiologic secretion.

Sodium, Hydrogen exchange type 1 and bile ductular secretory activity in the guinea pig

Biliary epithelial cells (BECs) express different Na(+), H(+) exchange (NHE) isoforms. In this study, the potential role of NHE in ductular bile secretion is assessed. Experiments were performed in guinea pig perfused livers and isolated BECs. Inhibition of NHE was achieved by hypotonic stress and by using the unspecific NHE inhibitor, amiloride, or the specific NHE 1 inhibitor, cariporide (HOE 642). Hypotonic stress inhibited basal bile flow by 46% and prevented secretin stimulation of bile flow by reducing biliary bicarbonate output by 50%. Secretin increased bile flow from 3.7 +/- 0.8 microL/min/g to 4.78 microL/min/g (P <.01); subsequent exposure to hypotonic stress decreased secretin-stimulated bile flow by 35% and biliary bicarbonate secretion by approximately 50%. Inhibition of NHE by amiloride or cariporide resulted in a similar reduction of secretin-stimulated bile flow and bicarbonate secretion. Basal bile flow was unaffected by the NHE inhibitors. In isolated guinea pig BECs, regulatory volume decrease and inhibition of NHE was demonstrated after hypotonic stress under basal and secretin-stimulated conditions. In contrast, hypotonic exposure inhibited Cl(-), HCO(3)(-) exchange activity in isolated BECs only during basal conditions but incompletely after secretin stimulation. Our study shows that hypotonic stress inhibits basal bile flow in the guinea pig by inhibition of Cl(-), HCO(3)(-) exchange. NHE1 is not involved in basal bile formation. Increased choleresis after ductular stimulation by secretin depends on intact NHE1 activity. These data indicate that BEC volume changes have profound effects on biliary secretory function.

Bile acid feeding induces cholangiocyte proliferation and secretion: Evidence for bile acid–regulated ductal secretion

Background & Aims: We have shown that taurocholate (TC) and taurolithocholate (TLC) interact in vitro with normal cholangiocytes, increasing DNA synthesis, secretin receptor (SR) gene expression, and adenosine 3',5'-cyclic monophosphate (cAMP) synthesis. To further extend these in vitro studies, we tested the hypothesis that bile acids (BAs) directly stimulate cholangiocyte proliferation and secretion in vivo. Methods: After feeding with TC or TLC (1% for 1–4 weeks), we assessed the following in vivo: (1) ductal proliferation by both morphometry and immunohistochemistry for proliferating cell nuclear antigen (PCNA) and measurement of [ 3H]thymidine incorporation; and (2) the effect of secretin on bile secretion and bicarbonate secretion in vivo. Genetic expression of H 3-histone and SR and intracellular cAMP levels were measured in isolated cholangiocytes. Results: After BA feeding, there was an increased number of PCNA-positive cholangiocytes and an increased number of ducts compared with control rats. [ 3H]Thymidine incorporation, absent in control cholangiocytes, was increased in cholangiocytes from BA-fed rats. In BA-fed rats, there was increased SR gene expression (approximately 2.5-fold) and secretin-induced cAMP levels (approximately 3.0-fold) in cholangiocytes, which was associated with de novo secretin-stimulated bile flow and bicarbonate secretion. Conclusions: These data indicate that elevated BA levels stimulate ductal secretion and cholangiocyte proliferation. GASTROENTEROLOGY 1999;116:179-186

Insulin inhibits secretin-stimulated ductal bile secretion in bile duct-ligated (BDL) rats by interaction with insulin receptors on cholangiocytes

Insulin inhibits secretin-stimulated ductal bile secretion in bile duct-ligated (BDL) rats by interaction with insulin receptors on cholangiocytes

Ductular Proliferation and Hepatic Secretory Function in Experimental Fascioliasis

Proliferation of bile duct-like epithelial cells is a common feature of extrahepatic biliary obstruction and it is also present in other forms of liver disease. Experimental infestation with Fasciola hepatica induces hyperplasia of ductular cells together with different functional alterations, such as hypercholeresis, in the rat. We have investigated the contribution of ductular biliary secretion to the hypercholeretic phenomenon in rats with experimental fascioliasis. Infestation was induced by oral administration of 20 metacercariae of F. hepatica. Twelve weeks later, histological study of the liver showed a hyperplastic reaction with proliferation of bile duct-like structures. Basal bile flow in infested animals was significantly higher than that of control animals (+ 17%), while biliary secretion of bile acids did not significantly differ between both groups. Bile flow increase was associated in parasitized animals with a significantly lower [ 14C]mannitol bile:plasma ratio (− 23%). Intravenous secretin administration (0.3 CU/l00 g body wt min) induced a significant increase in the biliary concentration of bicarbonate (+ 21%) and an enhancement of bile flow (+ 21%) only in the animals with ductular proliferation. Taurocholate infusion (0.5 nmol/l00 g body wt min) produced a similar bile flow increase both in control rats and in rats with proliferated biliary ductules. These results indicate that proliferated bile ductules and ducts spontaneously secrete bile in response to infestation by F. hepatica and that secretin-stimulated bile flow originates at the proliferated biliary structures.

Effects of digitoxin and lithium, used as a marker of passive Na transport, on secretin‐dependent bile flow in the pig

The present study was performed in anaesthetized pigs, and the first aim was to assess the role of Na,K-ATPase in secretin-dependent biliary HCO3 secretion (JbHCO3). Intra-arterial administration of the cardiac glycoside digitoxin (0.2 mg/kg-1) reduced hepatic Na K-ATPase activity, JbHCO3 and secretin-dependent bile flow by 24, 55 and 34% respectively. In the second part of this study lithium (Li) was used as a marker of passive Na transport to assess the electrochemical gradient for Na flux into bile duct lumen during secretin-stimulated bile flow and impeded biliary osmotic water flow by i.v. infusion of glucose. At plasma glucose 85 (73-96) mmol l-1, bile [Na] and [Li] exceeded their concentrations in plasma by 57 and 47% respectively. By using the Nernst equation, transepithelial potential difference (PD) during hyperglycaemia was estimated to be -6.2 (0 to -10.8) mV (ductal lumen negative), which corresponds to a [Li]bile/[Li]plasma ratio of 1.3 (1.0-1.5). The ratio was not significantly different from the observed [Li]bile/[Li]plasma ratio of 1.4 (1.3-1.5). It is concluded (1) that Na, K-ATPase is necessary for JbHCO3, probably by sustaining the cell membrane PD (cell interior negative) which is a driving force for apical electrogenic HCO3 secretion, and (2) transepithelial Li (and hence Na) flux is driven solely by the negative transcellular PD during secretin-stimulated bile flow in the pig.

Bile secretory function of intrahepatic biliary epithelium in the rat.

To shed light on ductular fluid secretion, hepatic histology and ultrastructure, cell proliferation and phenotypes, and several aspects of biliary physiology were studied in rats with ductular cell hyperplasia induced by either biliary obstruction (0-14 days) or 1-naphthylisothiocyanate (ANIT) feeding (0-28 days). In both groups of experimental animals, bile duct hyperplasia and spontaneous bile flow and secretin-induced choleresis increased with time of treatment in a linear fashion. Measurements of [14C]mannitol biliary entry and of biliary tree volume showed that the increase in both spontaneous and secretin-stimulated bile flow originated at the proliferated biliary structures. Ultrastructural examination, [3H]thymidine incorporation, and histochemical and immunohistochemical staining for various markers demonstrated that in both hyperplastic reactions the proliferated cells were the progeny of preexisting biliary epithelial cells and retained their characteristics. These results indicate that the increased bile secretory activity associated with either biliary obstruction or ANIT intoxication reflects a quantitative change due to the proliferation of biliary epithelial cells. Thus both models of bile ductular cell hyperplasia lend themselves to assessment of the transport function of intrahepatic biliary epithelium and its contribution to normal bile formation. In the present studies, we have estimated that net ductular secretion in the normal rat accounts for 10-13% of spontaneously secreted hepatic bile.

Dissociation of the alpha-adrenergic inhibitory effects on glucagon- and secretin-stimulated bile volume and on cyclic adenosine monophosphate production in the isolated perfused rat liver.

In the isolated perfused rat liver, glucagon increased glucose, cAMP, and bile production. Secretin increased cAMP in the effluent more and bile volume less than glucagon, but did not increase glucose output. When glucagon and secretin were infused together, the effect on cAMP was additive, but glucose output and bile volume were the same as with glucagon alone. The stimulation of bile production by glucagon was suppressed by phenylephrine but not by oxymetazoline, whereas the glucagon-induced cAMP increase in the effluent was suppressed by oxymetazoline in a dose-dependent manner, but not by phenylephrine. Glucagon-stimulated glucose output was not suppressed even when cAMP in the effluent was significantly suppressed by oxymetazoline. The secretin-induced stimulation of bile production was suppressed by phenylephrine, but not by oxymetazoline. Secretin-stimulated cAMP was suppressed more by oxymetazoline than by phenylephrine. The bile volume was not suppressed by phenylephrine alone either in the presence or in the absence of sodium taurocholate. These results indicate that the cholestatic effect of adrenergic agents is mediated by alpha 1-adrenergic receptors, whereas their cAMP suppressive effect is mediated by alpha 2-adrenergic receptors. The stimulatory effect of glucagon on cAMP production was more resistant to alpha-adrenergic agonists than to that of secretin. The dissociation by oxymetazoline of the effects of glucagon on cAMP production from its effect on glucose production is unexplained, whereas the significance of the secretin-induced increase in cAMP production is uncertain.

Effect of Somatostatin and Bombesin on Secretin-Stimulated Ductular Bile Flow in Dogs

The effects of somatostatin and bombesin on the choleresis produced by intraduodenal acid infusion were evaluated in dogs. Because of the documented effect of these agents on hormone release, serum gastrin and plasma secretin levels were monitored. Intraduodenal acid (12 mmol/h) increased bile flow and bile bicarbonate secretion and nearly doubled systemic plasma secretin levels. Bombesin significantly increased the bicarbonate-rich choleresis produced by intraduodenal acid and increased secretin release. Somatostatin inhibited completely the choleresis produced by 12 mmol/h of intraduodenal acid but did not significantly change systemic plasma secretin levels. Subsequent studies evaluated the effects of somatostatin (10 micrograms/kg . h) on bile flow and on systemic and portal plasma secretin concentrations stimulated by exogenous secretin administration and intraduodenal acid infusion. These studies demonstrated that somatostatin did not significantly change the choleretic response or the increases in plasma secretin produced by exogenous secretin. During duodenal acid infusion, somatostatin inhibited the choleresis and significantly decreased portal plasma secretin release. Evaluation of the relationship of the increase in bile flow to the increase in portal vein secretin concentrations, as well as comparison of the degree of inhibition of bile flow with the inhibition of secretin release produced by somatostatin, indicates that secretin produces approximately 80% of the choleresis produced by acid in the duodenum. Bombesin augments bile flow stimulated by infusion of acid into the duodenum by increasing secretin release, while somatostatin decreases bile flow produced by acid in the duodenum by directly inhibiting the release of secretin from the duodenal mucosa.

The role of cyclic AMP in canine secretin-stimulated bile flow

Cyclic nucleotide secretion rates in bile during the physiologic stimulation of ductular bile flow in dogs was evaluated by measurement of bile cyclic AMP concentration during the stimulation of secretin release by infusion of acid into the duodenum of dogs with chronic bile fistulas. The effects of PGA 1 and theophylline on secretin-stimulated bile flow and cyclic AMP secretin rates were also evaluated. Endogenous secretin stimulated bicarbonate-rich bile flow and decreased bile cyclic AMP concentration. PGA 1 significantly decreased secretin-stimulated bile flow but not bile cyclic AMP secretion. Theophylline did not alter secretin-stimulated bile flow or cyclic AMP secretion rates. These data indicate that based on cyclic AMP content in bile, secretin-stimulated ductular bile flow is unrelated to cyclic AMP metabolism.

Effect of glucagon on secretin-stimulated bile flow

The effect of glucagon on secretin-stimulated bile flow was evaluated in dogs with chronic biliary and gastric fistulas. Evaluation of the effects of secretin and glucagon alone on hepatic bile flow indicated that the calculated maximal response (CMR) values of the two agents were similar. Secretin increased the bicarbonate concentration in hepatic bile whereas glucagon did not, suggesting basic differences in mechanism of action. Administration of glucagon to secretin-stimulated bile flow produced an increase in bile flow while decreasing the bicarbonate concentration in secretin-stimulated bile. Since the maximal response for bile flow to glucagon and secretin was significantly greater than the maximal response to either agent alone, glucagon produced potentiation of secretin-stimulated bile. Glucagon increased the CMR value of secretin-stimulated bile from 513 mul/min for secretin alone to 692 mul/min for secretin and glucagon. This was associated with no significant change in the values of the respective D50S. These data suggest that glucagon produced a noncompetitive augmentation of secretin-stimulated bile flow and suggest that the two agents do not utilize the same receptor to stimulate bile flow.

Effect of theophylline of hepatic excretory function

ARTICLESEffect of theophylline of hepatic excretory functionJL Barnhart, and B CombesJL Barnhart, and B CombesPublished Online:01 Jul 1974https://doi.org/10.1152/ajplegacy.1974.227.1.194MoreSectionsPDF (1 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmailWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformationCited ByRole of Extracorporeal Drug Removal in Acute Theophylline Poisoning27 November 2012 | Medical Toxicology, Vol. 2, No. 4Effect of theophylline on glucagon and secretin stimulated bile flowDigestive Diseases and Sciences, Vol. 29, No. 3Effect of diethyl maleate on the biliary excretion rate of infused sulfobromophthalein-glutathioneBiochemical Pharmacology, Vol. 31, No. 16Biliary excretion of sulfobromophthalein compounds in normal and mutant corriedale sheep. Evidence for a disproportionate transport defect for conjugated sulfobromophthaleinHepatology, Vol. 1, No. 5Effects of phenobarbital and 3-methylcholanthrene pretreatment on the plasma half-life and urinary excretion profile of theophylline and its metabolites in ratsBiochemical Pharmacology, Vol. 28, No. 19The role of cyclic AMP in canine secretin-stimulated bile flowJournal of Surgical Research, Vol. 27, No. 1Simultaneous determination of theophylline and its metabolites in urine21 August 2008 | Current Medical Research and Opinion, Vol. 6, No. sup6Theophylline therapy in asthmatic children: single-dose studies21 August 2008 | Current Medical Research and Opinion, Vol. 6, No. sup6A possible mechanism of choleretic action of 3-(2,4,5-triethoxybenzoyl)-propoionic acid (AA-149) in dogsEuropean Journal of Pharmacology, Vol. 48, No. 1Erythritol and mannitol clearances with taurocholate and secretin-induced cholereses.J L Barnhart, and B Combes1 February 1978 | American Journal of Physiology-Endocrinology and Metabolism, Vol. 234, No. 2Dependence of the biliary excretion of iopanoic acid on bile saltsGastroenterology, Vol. 74, No. 2Urinary excretion of dye in dogs infused with BSP or its glutathione conjugateThe American Journal of Digestive Diseases, Vol. 23, No. 1The effect of bucolome on the canalicular bile formation and sulfobromophthalein transport maximum in the dogBiochemical Pharmacology, Vol. 25, No. 12Cyclic Amp in Secretin CholeresisGastroenterology, Vol. 70, No. 4Biliary Excretion of Metals22 September 2008 | Drug Metabolism Reviews, Vol. 5, No. 2Prostaglandin-induced choleresis in the ratExperientia, Vol. 31, No. 10Biliary Excretion of Xenobiotics14 February 2011 | CRC Critical Reviews in Toxicology, Vol. 4, No. 1Phenobarbital-enhanced biliary excretion of administered unconjugated and conjugated sulfobromophthalein (BSP) in the ratBiochemical Pharmacology, Vol. 24, No. 13-14Dosage of Theophylline in Bronchial AsthmaNew England Journal of Medicine, Vol. 292, No. 23Choleresis and hepatic transport mechanismsNaunyn-Schmiedeberg's Archives of Pharmacology, Vol. 290, No. 4 More from this issue > Volume 227Issue 1July 1974Pages 194-199 Copyright & PermissionsCopyright © 1974 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1974.227.1.194PubMed4843371History Published online 1 July 1974 Published in print 1 July 1974 Metrics

Saulfapyridine in Secretin Stimulated Pancreatic Juice and Bile of Cats

The combined treatment of cats with sulfapyridine and secretin is described. In conformance with other investigations, in which secretin was not used, the concentration of sulfapyridine in pancreatic juice was found to be just lower than that of blood, but an extremely high concentration of the drug was found in the bile. The drug is not diluted by the increased flow of juice either from pancreas or liver and tends to be independent of rate of flow. Blood concentration of sulfapyridine is more important. While there was no change in the percentage of free drug excreted in the pancreatic juice, 30 % of the free drug had been bound when excreted in the bile, indicating acetylation by the liver.