Vagal, Cholinergic Regulation of Pancreatic Polypeptide Secretion T. W. Schwartz, … , O. B. Schaffalitzky de Muckadell, F. Stadil J Clin Invest. 1978;61(3):781-789. https://doi.org/10.1172/JCI108992. Research Article The effect of efferent, parasympathetic stimulation upon pancreatic polypeptide (PP) secretion was studied in three ways: (a) Plasma PP concentrations increased in response to insulin-induced hypoglycemia in both normal subjects, from 11 pM (9.5-12.5) to 136 pM (118-147), n = 8 (median and interquartile range) and in duodenal ulcer patients, from 33 pM (21- 52) to 213 pM (157-233), n = 7. The PP response to hypoglycemia was diminished by atropine in normal subjects P( < 0.005) and completely abolished by vagotomy in the duodenal ulcer patients. (b) Electrical stimulation, 8 Hz, of the vagal nerves in anesthetized pigs induced an increase in portal PP concentrations within 30 s from 32 pM (28-39) to 285 pM (248-294), n = 12. Minimal stimulatory frequency was 0.5 Hz and maximal stimulatory frequency 8-12 Hz. Atropine inhibited the PP response to electrical stimulation. Median inhibition with 0.5 mg of atropine/kg body wt was 74%, range 31-90%, n = 6. The response was eliminated by hexamethonium. Adrenergic alpha and beta blockade did not influence the release of PP in response to vagal stimulation. (c) Acetylcholine stimulated, in a dose-dependent manner, the secretion of PP from the isolated perfused porcine pancreas, half-maximal effective dose being 0.19 μM; maximal PP output in response to 5 min stimulation was 228 pmol, range 140-342 pmol, n = 5. Atropine […] Find the latest version: https://jci.me/108992/pdf Vagal, Cholinergic Regulation of Pancreatic Polypeptide Secretion T. W. SCHWARTZ, J. J. HOLST, J. FAHRENKRUG, S. LINDKLER JENSEN, 0. V. NIELSEN, J. F. REHFELD, 0. B. SCHAFFALITZKY DE MUCKADELL, and F. STADIL, Institute of Medical Biochemistry, University of Aarhus, Arhus; Department of Clinical Chemistry, Bispebjerg Hospital, Copenhagen; Department of Surgical Gastroenterology C, Rigshospitalet, Copenhagen, Denmark A B S R A C T The effect of efferent, parasympathetic INTRODUCTION stimulation upon pancreatic polypeptide (PP) secre- Human pancreatic polypeptide was isolated by Chance tion was studied in three ways: (a) Plasma PP concen- et al. as a side fraction during insulin purification (1). trations increased in response to insulin-induced hypo- It is a 36 amino acid straight chain polypeptide with no glycemia in both normal subjects, from 11 pM (9.5- similarity in sequence to any other known hormone. 12.5) to 136 pM (118-147), n = 8 (median and inter- One or two aminoacids distinguish the known mam- quartile range) and in duodenal ulcer patients, from 33 malian pancreatic polypeptides (PP)l (1), whereas they pM (21-52) to 213 pM (157-233), n = 7. The PP re- have only 16 amino acids in common with the avian sponse to hypoglycemia was diminished by atropine in counterpart (2). normal subjects (P < 0.005) and completely abolished PP has been localized to secretory granules in a spe- by vagotomy in the duodenal ulcer patients. (b) Electri- cific endocrine cell type in the pancreas distinct from cal stimulation, 8 Hz, of the vagal nerves in anesthe- the A, B, D, and D, cells (3, 4). PP cells are found tized pigs induced an increase in portal PP concentra- both in the islets and in the acinar tissue and duct tions within 30 s from 32 pM (28-39) to 285 pM (248- epithelium. In some species PP cells are numerous 294), n = 12. Minimal stimulatory frequency was 0.5 in the extra-insular tissue and concentrated towards the Hz and maximal stimulatory frequency 8-12 Hz. Atro- duodenal part ofthe pancreas, whereas e.g., in the islets pine inhibited the PP response to electrical stimula- of the sheep the PP cells nearly outnumbers the insulin tion. Median inhibition with 0.5 mg of atropine/kg body cells (4). wt was 74%, range 31-90%, n = 6. The response was The action of PP has not yet been established al- eliminated by hexamethonium. Adrenergic alpha and though PP has been shown to affect many gastrointesti- beta blockade did not influence the release of PP in it PP response to vagal stimulation. (c) Acetylcholine stimu- nal functions (5). At present seems likely that acts lated, in a dose-dependent manner, the secretion of PP on the exocrine pancreatic tissue as a local regulator of from the isolated perfused porcine pancreas, half-maxi- secretion, in a way that may be conceived as an anti- mal effective dose being 0.19 ,uM; maximal PP output cholecystokinin and secretin-enhancing action (6, 7). in response to 5 min stimulation was 228 pmol, range It has recently been suggested that PP may also affect = satiety (8). 140-342 pmol, n 5. Atropine completely abolished During a meal PP concentrations in plasma increase this response. rapidly (9-13). The fool-mediated PP response consists The results of the present study together with the of a rapid primary phase (5-30 min) which is elimi- previously demonstrated poor PP response to food in nated by truncal vagotomy (10) and a prolonged sec- vagotomized patients, indicate that vagal, cholinergic ondary phase (0.5-6 h) which in man is reduced but stimulation is a major regulator of PP secretion. not abolished by vagotomy (10). The present study was This work was presented in part at the 11th Acta Endo- undertaken to investigate the effect of efferent para- crinologica Congress, 20-23 June 1977, Lausanne, Switzer- sympathetic stimulation on PP secretion. land, Abstract 161. 1977. Acta Endocritnol. 212 (Suppl.): 106. (Abstr.) ' Abbreviationis used in this paper: DU, duodenal ulcer; PP, Received for publication 18 Jtuly and in revised form 25 panereatic poly-peptides; VIP, vasoactive intestinal polypep- October 1977. tide. The Jouirnal of Clinical Investigation Volunme 61 March 1978 781-789 781 MIETHODS tweeni-assay coefficient of variation tested in 10 consecutive assays at concentrations of 30 and 75'pM was 12.8 and 12.1%. Radioimnmu noassay for paticreatic polypeptide Accuracy. Measurements of PP in plasma with added PP, and in dilutions of perfusate from the isolated panicreas (see Anitiserum. Anti-PP serumll (146-5), at generouis gift from below), porcine plasma, and human plasmla yielded results Drs. R. E. Chance and N. E. Moon (Eli Lilly & Co., Indianap- which deviated <20% from the expected values. The follow- olis, Ind.), was raised in a rabbit against subcutaneously in- ing specimens were exposed to gel permeation chromiiatog- jected highly purified bovine PP (BPP) coupled to albumin raphy: (a) perfusate from the isolated porcine pancreas during and mixed with complete Freund's adjuvant. The anltiserum stimulation with acetylcholinie; (b) porcine plasma obtained was used at a final dilution of 1/7.5 x 106. from the portal vein during electrical stimulation of the vagus Tracer. HighlyIpurified bovine PP was iodinlated by a nerve; and (c) human plasma obtained during in.sulini hypo- chloramine T method: 1 mCi 1251 (Behrinig-Werke AG, Mar- glycenmia. The gel permeation chromatography was performed burg/LLahi, West Germclany), 0.24 numlol (1 ,ug) highly pturified at 4°C on 10 x 1,000 mm Sephadex G-5( superfine columns BPP (a gift from Dr. Chance, Eli Lilly & Co.), and 18 nmol eluted with 1.0 M acetic acid with 2% equine serum and 0.2% (5 ,g) chloramine T was mixed in a total volume of 0.023 ml/ bovine serumii albumin. The fractions were lvophilize(d and 0.05 M sodium phosphate buffer, pH 7.4. The reactioni was reconstituted in barbitonie buffer 0.02 M, pH 8.4. In everv case terminated after 20 s by the addition of 26 nmol (5 ,ug) sodiun only one major immunoreactive peak with elution position metabisulfite in 0.010 ml sodium phosphate buffer. Theni 1.2 corresponding to purified PP was found, Fig. 1. Wheni plasma gnmol of potassium iodide in 0.1 nl wvas added followed by 0.2 ml of equine serum. The tracer was purifiedl on a 10 x 1,00( mm Sephadex G-50 superfine columni eluted with amlnmonium bicarbonate,(0.25 Xi, pH 8.2, at 4°C. The fractioins froml the 200- A ascending part of the 1251_PP peak gave the lowest unspecific binding without antibody (1-3%) and the highest binding in antibody surplus (90-95%). The specific radioactivity of the 150 - tracer was calculated to 200-250 /.Ci/4g (0.8-1.05 x 106 Ci/ m10ol). Standard. Highly purifiedl humclan PP (a gift from Dr. 100 - Chance, Eli Lilly & Co.) was usedl as standard. x in so- Assaly condition.s. Incubation was carriedl oUt 0.02 E dium barbitonie buffer, pH 8.4, with 0.2% bovine serumii al- 0C 50 - bumin (Ortho Pharmaceutical Corp., Raritani, N. J.) and 0.6 mnM thiomersal. The incubationi volume was 1.5 ml. In assays w 0- of plasma the saimple volume comprised 1/20 of the incubation UJQ- volume and in other assays at most 1/10 of the incubation CL volume. To obtain comparable incubation coniditions "hor- B mnone-free" plasma, twice treated with charcoal, was added to -J the standard and the same volume of buffer was added to the 0 50 - plasmiia samples. Incubation for 3 days was used in all assays a. except in assays on column eluates, where preincubation for 0 2 days was followed by 1 day of incuibation with tracer. 25 - Separation. Separation was performed with plasma- w Ir coated charcoal (Merck article 2186, Merck AG, Darmstadt, 0 West Germany). To each tube 0.5 ml of a preincubated char- z 0- coal slurry, 0.25 ml charcoal 40 g/liter and 0.25 ml outdated 0L plasma, was added.