Adrenergic effects secretionof epidermalgrowth factor

Gut, 1985, 26, 920-927

Adrenergic effects on secretion of epidermal growthfactor from Brunner's glandsP SKOV OLSEN, S S POULSEN, AND P KIRKEGAARD

From the Department of Clinical Chemistry ML, Department of Surgery C and Laboratory ofExperimental Pathology, Rigshospitalet and Department ofAnatomy B, University of Copenhagen,Copenhagen, Denmark

SUMMARY The influence of the sympathetic nervous system and adrenergic agonists on flow rateand secretion of epidermal growth factor (EGF) from Brunner's glands has been investigated inthe rat. Chemical sympathectomy by administration of 6-hydroxydopamine increased volumesecretion and output of EGF from Brunner's glands but depleted the glands of EGF. Infusion ofnoradrenaline, an alpha-adrenergic agonist, inhibited basal and vasoactive intestinal polypeptide(VIP) stimulated flow rate and output of EGF from Brunner's glands and increased the amountof EGF in the tissue. Vasoactive intestinal polypeptide also increased the amount of EGF inBrunner's gland tissue and this was unchanged after simultaneous infusion of VIP andnoradrenaline as well as VIP and isoproterenol, a beta-adrenergic agonist. Isoproterenol had noeffect on basal and VIP stimulated secretion of EGF from Brunner's glands. The presence ofPAS-positive mucus in Brunner's glands was unchanged during infusion of noradrenalinewhereas VIP induced a depletion of Brunner's gland mucus which in turn was prevented bysimultaneous infusion of noradrenaline. This study indicates that the sympathetic nervous systeminfluence the volume secretion, output of EGF and mucus content in Brunner's glands probablyby activation of alpha-adrenergic pathways.

The glands of Brunner are localised in the sub-mucosa of the proximal duodenum and experimen-tal studies have indicated that the main function ofBrunner's glands is to protect the duodenal mucosaagainst damage by the acid chyme ejected from thestomach.1 2 Duodenal ulcers are situated in theproximal duodenum in the Brunner's gland area andrecent studies have demonstrated that an impairedBrunner's gland secretion might be involved in thedevelopment of experimental duodenal ulcers.f5The secretion from Brunner's glands contains

bicarbonate, mucus and epidermal growth factor(EGF).6 7 Epidermal growth factor is a mitogenicpeptide comprising 53 amino acids.8 The peptide isproduced in the submandibular glands and Brun-ner's glands and is present in large amounts inurine. Several studies have shown an exocrinesecretion of EGF from the submandibular glandsand recently exocrine secretion of the peptide fromBrunner's glands has been reported.llL Intragas-tric instillation of EGF increases the synthesis andAddress for correspondence: P Skov Olsen, Department Surgery C, 2122,Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark.Received for publication 1 November 1984

contents of DNA and RNA in the gastroduodenalmucosa13 and intraduodenal as well as intragastricinstillation of EGF prevents the development ofexperimental duodenal and gastric ulcers in therat.14 15

In the submandibular glands EGF is localised tothe granulated convoluted tubular cells which areinnervated by adrenergic nerves and alpha-adrenergic agonists stimulate exocrine secretion ofEGF from the submandibular glands.1' 16 17 Brun-ner's glands are also innervated by adrenergicnerves but the effect of adrenergic agonists onsecretion from Brunner's glands has not beenelucidated.18 19The present study was undertaken to investigate

the influence of the sympathetic nervous system andadrenergic agonists on basal and VIP stimulatedflow rate and secretion of EGF from Brunner'sglands in the rat.

Methods

EXPERIMENTAL PROCEDUREOne hundred and four male Wistar rats were used,

920

on October 5, 2021 by guest. P

rotected by copyright.http://gut.bm

j.com/

Gut: first published as 10.1136/gut.26.9.920 on 1 S

eptember 1985. D

ownloaded from

http://gut.bmj.com/

Adrenergic effects on Brunner's glands

weighing approximately 200 g at the time of surgery.The rats were fasted overnight before the experi-ment. They had free access to water and were keptin raised meshbottom cages to prevent coprophagy.Under ether anaesthesia a 0-8 mm polyethylenecatheter was placed in a jugular vein for infusions.For preparation of a duodenal pouch, the abdomenwas opened by a midline incision. A ligature wasplaced around the pyloric ring, and another one8-10 mm distal to the pylorus, just proximal to theentrance of the common bile and pancreatic duct.Through an incision in the distal duodenum the tipof a polyethylene catheter was introduced throughthe distal ligature into the duodenal pouch where-after the ligature was tightened. For drainage of thestomach, a polyethylene catheter was placed in thestomach through a stab wound in the forestomachand secured by a purse string suture.

For collection of duodenal and gastric juice thecatheters were connected to glass syringes. The ratswere placed in Bollman cages and after one hour ofrecovery, the infusion was started. Brunner's glandsecretion was collected during infusion of thefollowing drugs for five hours in a volume of 2mlxh-1: noradrenaline 1 48 ,umolxkg'1xh-1 (2501zgxkg7'xh-') (DAK, Copenhagen, Denmark) andisoproterenol in a dose of 1X18 /umol x kg'x h-' (250,ugxkg-1) (DAK, Copenhagen, Denmark). Porcinevasoactive intestinal polypeptide (VIP) (Gas-trointestinal Hormone Unit, Karolinska Institute,Stockholm, Sweden) was infused in a dose of 330pmolxkglxh-l (1000 ngxkg7lxh-1) alone or incombination with either noradrenaline 1-48,umolxkgl xh-1 or isoproterenol 1*18 ,umolxkg-1xh-1. To investigate the effect of chemical sym-pathectomy2" on Brunner's gland secretion eightrats received an intraperitoneal injection of 6-hydroxydopamine 600 ,umolxkg1l (150 mgxkg-l)(Sigma Chem. Comp., St Louis, USA). After sevendays Brunner's gland secretion was collected for fivehours as described above during infusion of saline(NaCl 0*154 mol/l) in a volume of 2 mlxh-1. Eightrats given saline served as controls.At the end of each infusion blood was drawn from

the inferior vena cava and the volume of Brunner'sgland secretion was determined. The duodenalpouch was removed and together with serum storedat -20°C for later determination of EGF.For histochemical investigations of Brunner's

glands rats in groups of 10 had a duodenal pouchprepared as described above. The following agentswere infused in a volume of 2 mlxh-1 for five hours:noradrenaline 1X48 ,umolxkg-1xh-', VIP 330pmolx1kg'xh-1 and simultaneous infusion of thesame doses of VIP and noradrenaline while 10 ratsserved as controls and received saline. At the end of

the infusion the duodenal pouch was fixed in 10%formalin and prepared for histological investigation.

LABORATORY ANALYSESEpidermal growth factor was measured with ahomologous radioimmunoassay using antibody 8136as described elsewhere.7 Detection limit of the assayis 0-06 nmol/l and coefficient of variation approxi-mately 0*10 for values between 0*06 nmol/l and 4nmol/l. Purified rat submandibular EGF was usedfor calibration and production of tracer. The duode-num was extracted using ion exchange chromatogra-phy as described.7 Duodenal juice and serum wastested undiluted. For evaluation of the assay,calibration curves were prepared with charcoalstripped serum and duodenal juice (unstimulated)and compared with a calibration curve performed inassay buffer. Charcoal precipitation was carried outby adding charcoal (Sigma Chem Co, St Louis,USA) 5 g per 100 ml rat serum or duodenal juice.After stirring for 20 min at 4°C the suspension wasseparated by centrifugation at 6000 g for 60 min.

HISTOLOGICAL INVESTIGATIONSThe presence of VIP-containing nerves in Brunner'sglands was investigated immunohistochemically.Five rats were fixed by perfusion with 4% para-formaldehyde. The duodenum was removed andpostfixed in paraformaldehyde for 24 hours. Thetissues were then rinsed for 48 hours in 20% sucroseand frozen in melting freon. Cryostat sections 10 ttmin thickness were cut at -20°C. Sections werestained for VIP by the peroxidase-antiperoxidasetechnique (PAP).21 The VIP antiserum (CambridgeResearch Biochemicals, UK) was diluted 1:400 and1:1600. For controls the sections were incubatedwith non-immune rabbit serum and the primaryantiserum preabsorbed with excess amounts ofporcine VIP 10 ,tg/ml. To evaluate the amount ofmucus in Brunner's glands, histologic sections werestained with PAS-haematoxylin-aurentia.

STATISTICSFor statistical evaluation of the data, the Mann-Whitney U-test was used. P-values of 60-05 wereconsidered to be significant. All results are given asmedian and total range.

Results

Infusion of noradrenaline, an alpha-adrenergicagonist, reduced the spontaneous secretion fromBrunner's glands. The contents of EGF in Brunner'sgland tissue, however, increased whereas the totaloutput of EGF decreased since the concentration ofEGF in duodenal juice was unchanged. In contrast

921



j.com/


eptember 1985. D

ownloaded from

http://gut.bmj.com/

Skov Olsen, Poulsen, and Kirkegaard

infusion of the beta-adrenergic agonist, isopro-terenol, did not result in changes in comparison withcontrols (Table 1, Fig. 1). Chemical sympathectomyby 6-hydroxydopamine increased the secretory rateas well as the total output of EGF in duodenal juicewhereas the amount of EGF in the tissue decreased(Table 1, Fig. 1). Vasoactive intestinal polypeptideincreased Brunner's gland secretion and the totaloutput of EGF but in contrast with sympathectomythe contents of EGF in the tissue were increased.The stimulatory effect of VIP was counteracted bysimultaneous infusion of noradrenaline but theamount of EGF in the duodenal tissue was the sameas after infusion of VIP alone (Table 2, Fig. 2).Isoproterenol had no effect on VIP stimulatedBrunner's gland secretion nor on the output of EGFand the amount of peptide in the tissue was

unchanged. None of the groups investigated had a

median concentration of EGF serum above thedetection limit of the assay.The calibration curves prepared in serum and

duodenal juice were identical (Fig. 1). Because ofnon-specific interference, however, a higher zero-binding was found compared with the buffer calibra-tion curve. No indications of the presence of EGFdegrading factors in serum or duodenal juice was

found because the buffer calibration curve could besuperimposed on the calibration curve performed inserum and duodenal juice. In no instance thebackground was higher than O 5% of the totalcounts bound.

Immunohistochemically, VIP containing nervefibres were found in Brunner's glands (Fig. 4). Thenerve fibres were seen in close association with thesecretory acini of Brunner's glands. No im-munoreaction was observed in sections incubatedwith the primary antiserum preabsorbed with excessamounts of porcine VIP nor in sections incubated

Table 1 Effect ofadrenergic agonists and6-hydroxydopamine on secretion fromBrunner's glands

EGFin EGF EGFinduodenal output duodenum

Treatment No Volume juice fmoll fmollml/S h pmol/l S h duodenum

Control 8 0-95 260 220 425(saline) (0-70-1-40) (95-470) (130-390) (275-625)

Noradre- 8 0-40t 265 105* 1075tnaline (0-20-0.55) (150-650) (50-260) (815-1475)

Isopro- 8 1-05 205 235 550terenol (0-65-1-20) (105-645) (115-420) (225-700)

6-hydroxy- 8 1-55* 650t 1005t 225*dopamine (1-30-1-90) (355-910) (515-1365) (<60-400)

Values are given as median and total range. *: p<0.05 andt: p<0-01 as compared with control.

14

12

* BufferA Seruma Duodernl juice

C,.)

a. .6.

(nmol/l1)

Fig. 1 Standard calibration curves for rat epidermalgrowth factor radioimmunoassay prepared in buffer, ratserum and rat duodenal juice.

with non-immune rabbit serum. At histologicalexamination, Brunner's glands in the control groupwas rich in PAS-positive mucin and the presence ofmucus was identical after infusion of noradrenaline.After infusion of VIP the main part of the secretoryacini became PAS-negative and thus depleted ofmucus. This effect of VIP was partly prevented bysimultaneous infusion of noradrenaline (Figs. 5 and6).

Table 2 Effect ofadrenergic agonists on VIP stimulatedsecretion from Brunner's glands

EGFin EGF EGFinduodenal output duodenum

Treatment No Volume juice fmoll fmollmilS h pmol/l S h duodenum

Control 8 0-95 260 220 425(saline) (0.701-40) (95-470) (130-390) (275-625)VIP 8 1-90t 320 620* 650*

(1*60(2-15) (200-415) (340-730) (475-950)VIP+nor- 8 0-75t 220 165* 800tadrenaline (0-50-0.90) (150-315) (90-245) (525-1250)VIP+iso- 8 2-00 305 730 725tproterenol (1-20-2-60) (170-535) (410-1070) (425-1075)

Values are given as median and total range. *: p<0-05 andt: p<0-01 as compared with controls; t: p<0-01 as compared withinfusion of VIP.

922



j.com/


eptember 1985. D

ownloaded from

http://gut.bmj.com/


b0

b0

0I

000

I

0

0

8* aI._Sa &9>£t a4jvs

0

aI.

.

_

-1600 1600mC)'n1

*1200 a. ;1200-c _

0

c _3 E800 = 800

c o

400 m 4003_

0

bS

a

8

-0

i -

5 tqoo0

.

0

a b0 @

8 So 0

0

80

c

4

i__-?

O- *J

Fig. 2 Effect ofadrenergic agonists and chemicalsympathectomy (6-hydroxydopamine) on total output ofEGFfrom Brunner's glands and the corresponding amountofEGF in the duodenum at the end of the experiment are

shown. a: p<OO5 and b:p<O0O1 as compared with control.(Median and total range ofeight rats).

Discussion

Previous investigations have shown that a humoralmechanism is important in regulation of secretionfrom Brunner's glands.6 22 A nervous effect on thesecretion has also been reported.23 24 Wright et aldemonstrated a cholinergic control of Brunner'sgland secretion as cholinomimetic agents and directstimulation of the cut ends of the vagal nerve

stimulates Brunner's gland secretion. The lattereffect could be eliminated by infusion of atropine.23While the vagal nerve was supposed to stimulate

Brunner's gland secretion the sympathetic nervous

system has been suggested to reduce the secretionbecause electrical stimulation of the splanchnicnerves reduced the secretory output from theglands, while section of the splanchnic nervesincreased the secretion.23 The latter effect couldalso be prevented by atropine indicating that thesplanchnic nerves carries inhibitory fibres whichinfluence a cholinergic tonus on Brunner's glands.

In the present study the inhibitory effect of thesympathetic nervous system on the Brunner's glandsecretion was confirmed. Chemical sympathectomy

Fig. 3 Effect ofadrenergic agonists on VIP stimulatedsecretion from Brunner's glands. The total output ofEGFfrom Brunner's glands and the corresponding amount ofEGFin the duodenum at the end ofthe experiment are

shown. a:p<OOS and b: p<OOJ as compared with control;c: p<O0O1 as compared with infusion of VIP. (Median andtotal range ofeight rats).

with 6-hydroxydopamine increased the flow rate andoutput of EGF from Brunner's glands whereas thealpha-adrenergic agonist, noradrenaline, inhibitedthe secretion. These results are consistent with thefinding of adrenergic nerves surrounding the secre-tory acini of Brunner's glands which suggests afunctional adrenergic innervation of the glands.'8

In this study we confirm the previous finding ofVIP containing nerves in Brunner's glands in therat."' By means of the conventional PAP techniqueused in the present study we found VIP containingnerves between the glands and in close associationto the secretory acini (Fig. 4) suggesting a VIP-ergicinnervation of the rat Brunner's glands. Vasoactiveintestinal polypeptide was found to increase Brun-ner's gland secretion, total output of EGF and toincrease the contents of EGF in the glands. Incontrast noradrenaline inhibited VIP stimulatedsecretion of EGF but did not influence the increasedamount of EGF in the tissue observed after infusionof VIP. This and the observed effect of noradrena-line and chemical sympathectomy on secretion andcontents of EGF in Brunner's glands (Figs. 2 and 3)suggests that the adrenergic nerves innervating

1600

o 1200CEU)l-~

0E" 800

CD4-D

w 400

0

1600

mC)_.

-1200 'C

CQ

c

3'800 3

0

0.a

400 m

L0

0

S

923

1-

li

c



j.com/


eptember 1985. D

ownloaded from

http://gut.bmj.com/

Skov Olsen, Poulsen, and Kirkegaard

Fig. 4 VIP immunoreactive nerves in Brunner's glands of the rat visualised by means of the peroxidase-antiperoxidase(PAP) technique. The VIP immunoreactive fibres arefound between the secretory acini and in close association to these(arrows) (x335).

Brunner's glands mainly influence the release ofEGF though the possibility of an increased synthesisof EGF cannot be excluded. On the other hand itseems likely that VIP increases the synthesis of EGFas VIP induced secretion does not deplete the glandsfrom EGF.

Substantial evidence has accumulated showingthat cholinergic, adrenergic and VIP-containingnerves innervate and thereby influence the secretionfrom Brunner's glands.18 23 24 A coexistence of VIPand acetylcholine in secretory nerves has beenreported in the cat submandibular gland and com-bined biochemical and functional studies have indi-cated that acetylcholine probably acts as a classicalneurotransmitter, while VIP serves as a neuromodu-lator that increases the affinity of the receptor toacetylcholine.25 A similar effect on rat Brunner'sglands has been suggested as combined infusion ofVIP and acetylcholine has a more potent effect onthe output of EGF than infusion of each of thesubstances alone and furthermore the VIP inducedsecretion from the glands can be prevented by

atropine.12 Atropine has, however, also been foundto prevent the increased secretion from Brunner'sglands after section of the greater splanchnicnerves23 and the observed effect of noradrenalineand chemical sympathectomy in the present studysuggests adrenergic nerves to have an inhibitoryeffect on Brunner's gland secretion. Furthermore,VIP has previously been shown not only to increasethe secretion but also to deplete Brunner's glands ofmucus.24 We found noradrenaline to prevent theVIP induced depletion of mucus from Brunner'sglands indicating that noradrenaline inhibits notonly the flow rate and secretion of EGF but alsoinfluence the secretion of mucus.

In the present study exocrine secretion of EGFwas observed. Both mucus and EGF is thought to beprotective factors in the gastroduodenal mucosa26 27and a decrease in the exocrine secretion of EGFfrom Brunner's glands has been observed during thedevelopment of experimental duodenal ulcers. 14The role of the sympathetic nervous system inprotection of the gastroduodenal mucosa is un-

924



j.com/


eptember 1985. D

ownloaded from

http://gut.bmj.com/


Fig. 5 PAS-positive mucus in the secretory acini ofBrunner's glands. (a) control. (b) after infusion of vasoactive intestinalpolypeptide VIP 330pmol x kg' x h' forfive hours and (c) following infusion ofVIP and noradrenaline 1-48 umol xkg-' x h' forfive hours. Infusion ofVIP is followed by depletion ofmucus. This effect is counteracted by simultaneousinfusion ofnoradrenaline. PAS-haematoxylin-aurentia (x 550).

known. The observed effect of noradrenaline andsympathectomy on the amount of mucus and EGFin Brunner's glands and the effect on the output ofEGF from the glands suggests that an increasedactivity in the sympathetic nervous system or an

increased level or circulating catecholamines woulddecrease the protection of the duodenal mucosa andthereby facilitate the development of duodenalulcers.

In conclusion, this study suggests that the sym-

925



j.com/


eptember 1985. D

ownloaded from

http://gut.bmj.com/

926 Skov Olsen, Poulsen, and Kirkegaard

10 Control VIP

92- 0 m

z 10- Noradrencline VIP-1 noradrenaline

2 -IU1,,

0 1 2 3 0 1 2 3PAS-reaction

Fig. 6 PAS-reaction for mucus in the secretory cells ofBrunner's glands after infusion ofnoradrenaline 1 48 umolx kg-' x h-', VIP 330 pmol x kg-' x h-' and simultaneousinfusion ofboth VIP and noradrenaline. Grading ofPAS-reaction: 0 = PAS-negative; 1 = 1-2 small glandularareas with PAS positive reaction; 2 = more than two smallareas PAS-positive, but not the whole gland; 3 = allsecretory cells positive. Noradrenaline had no effect.Significant less PAS-positive mucus was seen after infusionof VIP (p<0-01, x2 test). This was counteracted bysimultaneous infusion ofnoradrenaline (p<0.005).

pathetic nervous system influences the flow rate andsecretion of EGF and mucus from Brunner's glandsby activation of alpha-adrenergic receptors.

The technical assistance of Bente Hansen-Schwartz,Birgit Walther J0rgensen and Henny Ploeger iswarmly acknowledged as is the fruitful discussionswith Dr Ebba Nex0. This study was supported bygrants from the Danish Medical Research Council(12-3933), the NOVO Foundation and the DanishHospital Foundation for Medical Research. Regionof Copenhagen, The Faroe Islands and Greenland(49/83).

References

1 Florey HW, Jennings MA, Jennings DA, CasteoO'Connor R. The reactions of the intestine of the pig togastric juice. J Pathol Bacteriol 1939; 49: 105-23.

2 Griffith CA, Harkins HN. The role of Brunner's glandsin the intrinsic resistance of the duodenum to acid-peptic digestion. Ann Surg 1956; 243: 160-72.

3 Hartiala K, Ivy AC, Grossman MI. Effect of feedingcinchophen on secretion of juice by duodenal glands indog. Am J Physiol 1950; 162: 110-4.

4 Perkins WE, Green TJ. Effect of 3,4-toluenediamineon output from in situ rat Brunner's glands pouches.Proc Soc Exp Biol Med 1975; 149: 991-4.

5 Kirkegaard P, Poulsen SS, Halse C, Loud FB, SkovOlsen P, Christiansen J. The effect of cysteamine on

the Brunner gland secretion in the rat. Scand JGastroenterol 1981; 16: 93-6.

6 Kirkegard P, Skov Olsen P, Poulsen SS, Holst JJ,Schaffalitsky de Muckadell OB, Christiansen J. Effectof secretin and glucagon on Brunner's gland secretionin the rat. Gut 1984; 25: 264-8.

7 Skov Olsen P, Nex0 E. Quantitation of epidermalgrowth factor in the rat. Identification and partialcharacterization of duodenal EGF. Scand J Gas-troenterol 1983; 18: 771-6.

8 Gregory H. Isolation and structure of urogastrone andits relationship to epidermal growth factor. Nature1975; 257: 325-7.

9 Hollenberg MD. Epidermal growth factor-urogastrone, a polypeptide acquiring hormonal status.Vitam Horm 1979; 37: 69-110.

10 Murphy RA, Pantazis NJ, Papastavros M. Epidermalgrowth factor and nerve growth factor in mouse saliva:a comparative study. Develop Biol 1979; 71: 356-70.

11 Skov Olsen P, Kirkegaard P, Poulsen SS, Nex0 E.Adrenergic effects on exocrine secretion of rat subman-dibular epidermal growth factor. Gut 1984; 25:1234-40.

12 Kirkegaard P, Skov Olsen P, Poulsen SS, Nex0 E.Exocrine secretion of epidermal growth factor fromBrunner's glands. Stimulation by VIP and acetylcho-line. Regulatory Peptides 1983; 7: 367-72.

13 Dembinski A, Gregory H, Konturek SJ, Polanski M.Trophic action of epidermal growth factor on thepancreas and gastroduodenal mucosa in rats. J Physiol1982; 325: 35-42.

14 Kirkegaard P, Skov Olsen P, Poulsen SS, Nex0 E.Epidermal growth factor inhibits cysteamine-inducedduodenal ulcers. Gastroenterology 1983; 85: 1277-83.

15 Skov Olsen P, Poulsen SS, Kirkegaard P, Nex0 E. Therole of submandibular saliva and epidermal growthfactor in gastric cytoprotection. Gastroenterology1984; 87: 103-8.

16 Gresik EW, Van der Noen H, Barka T. Epidermalgrowth factor-like material in rat submandibular gland(1). Am J Anat 1979; 156: 83-9.

17 Alm P, Bloom GD, Carlsoo B. Adrenergic andcholinergic nerves of bovine, Guinea pig and hamstersalivary glands. A light and electron microscopic study.Z Zellforsch 1973; 138: 407-20.

18 Stach VW, Hung N. Light microscopic and histo-chemical results on the innervation of Brunner's glandsin the duodenum of laboratory animals. Anat Anz1978; 144: 253-35.

19 Hartiala KJV, Toivonen T. Studies on the effect ofadrenaline and noradrenaline on the duodenal secre-tion in dog. Acta Physiol Scand 1954; 31: 125-30.

20 Thoenen H, Tranzer JP. Chemical sympathectomy byselective destruction of adrenergic nerve endings with6-hydroxydopamine. Naunyn-Schmiedebergs ArchPharmacol 1968; 261: 271-8.

21 Sternberger L. In: Immunohistochemistry EnglewoodCliffs, New York: Prentice Hall, 1974: 129-171.

22 Florey HW, Harding HE. A humoral control of thesecretion of Brunner's glands. Proc R Soc Lond B1935; 117: 68-77.

23 Wright RD, Jennings MA, Florey HW, Lium R. The



j.com/


eptember 1985. D

ownloaded from

http://gut.bmj.com/

Adrenergic effects on Brunner's glands 927

influence of nerves and drugs on secretion by the smallintestine and an investigation of the enzymes inintestinal juice. Q J Exp Physiol 1940; 166: 73-120.

24 Kirkegaard P, Lundberg JM, Poulsen SS, Skov OlsenP, Fahrenkrug J, Hokfelt T, Christiansen J. Vasoactiveintestinal polypeptidergic nerves and Brunner's glandsecretion in the rat. Gastroenterology 1981; 81: 872-8.

25 Lundberg JM. Evidence for coexistence of vasoactiveintestinal polypeptide (VIP) and acetylcholine in

neurons of cat exocrine glands. Morphological, bioche-mical and functional studies. Acta Physiol Scand 1981;suppl: 496: 1-57.

26 Allen A, Garner A. Mucus and bicarbonate secretionin the stomach and their possible role in mucosalprotection. Gut 1980; 21: 249-62.

27 Konturek SJ, Radecki T, Brzozowski T et al. Gastriccytoprotection by epidermal growth factor. Gas-troenterology 1981; 81: 438-43.



j.com/


eptember 1985. D

ownloaded from

http://gut.bmj.com/

Documents

Adrenergic effects secretionof epidermalgrowth factor