Viktor Mutt

Galanin - a novel biologically active peptide from porcine intestine

The isolation of a novel biologically active peptide, designated galanin, is described. The peptide was discovered by the detection of its C‐terminal amide structure in porcine intestinal extract using a chemical method. It was found that galanin consists of 29 amino acids and the complete amino acid sequence is: contract smooth muscle preparations from the rat and to cause a mild and sustained hyperglycemia in dog.

Characterization of a gastrin releasing peptide from porcine non-antral gastric tissue

Abstract A heptacosapeptide with potent gastrin releasing activity has been isolated from porcine non-antral gastric and intestinal tissue. The amino acid sequence suggested from a preliminary study on the gastric peptide is: Ala-Pro-Val-Ser-Val-Gly-Gly-Gly-Thr-Val-Leu-Ala-Lys-Met-Tyr-Pro-Arg-Gly-Asn-His-Trp-Ala-Val-Gly-His-Leu-Met-NH2. Striking homology in the C-terminal region is seen with bombesin, accounting for the similar bioactivities of the two peptides. Some structural resemblance with porcine cholecystokinin in the N-terminal region is noted.

A galanin-like peptide in the central nervous system and intestine of the rat

Galanin (GAL), a 29 amino acid peptide, was recently isolated from the small intestine of pigs. In the present study an antiserum towards porcine GAL has been developed and used for radioimmunoassay and immunohistochemical studies. We now report that GAL-like immunoreactivity occurs in wide-spread systems in the rat CNS and intestine.

N-terminally extended somatostatin: The primary structure of somatostatin-28

Somatostatin, first isolated from ovine hypothalamic extracts [l], has been characterized as a tetradecapeptide [2], and the same peptide has been obtained from porcine hypothalamus [3]. Somatostatin-like immunoreactivity and bioactivity are widely distributed in the central nervous system and in the digestive tract tissues [4-71. Size heterogeneity described in somatostatin-like immunoreactive materials [3,6,8,9] raised the possibility of the existence of prohormonal forms of this molecule [lO,l 11. During the purification of porcine intestinal somatostatin differences were noticed in the chromatographic behaviour of immunoreactive fractions and synthetic somatogtatin-14 [ 121. A novel intestinal peptide was then isolated and partly characterized as an N-terminally extended form of somatostatin [ 131. We report here the primary structure of this intestinal peptide which has been found to be an octacosapeptide, somatostatin-28. The results establish size heterogeneity in the somatostatin family of peptides. Sequence comparison between somatostatin-28 and prohormones also suggest that it may be a precursor of somatostatin-14.

Neuropeptide K: Isolation, structure and biological activities of a novel brain tachykinin

A 36 amino acid residue peptide, which contains a substance K sequence at its C-terminus has been isolated from porcine brain extracts. The primary structure of the peptide, designated neuropeptide K (NPK), was found to be: (sequence; see text) This N-terminally extended form of substance K is present in a high concentration in the brain. The peptide is highly biologically active with regard to gallbladder contraction, protein extravasation, hypotension and bronchial smooth muscle spasm and may act as an additional tachykinin neuromessenger.

Distribution of galanin-like immunoreactivity in the gastro-intestinal tract of several mammalian species.

SummaryThe distribution of galanin-immunoreactive (GAL-IR) neurons was mapped in detail in the gastro-intestinal tract of the rat, mouse, guinea-pig and pig by use of the indirect immunofluorescence technique. GAL-IR cell bodies were found in both the submucous and the myenteric plexus, with considerably higher numbers in the former ganglia. The largest number of GAL-IR perikarya was seen in the duodenal submucous plexus of the pig. With some (single) exceptions, GAL-IR cell somata were not observed in the myenteric plexus of the pig and guinea-pig, and in the submucous plexus of the esophagus and the stomach of the guinea-pig.GAL-IR fibers ocurred in most parts of the gastro-intestinal tract. In the lamina propria a few non-varicose, weakly fluorescent fibers were noted in the mouse and rat, whereas in the pig and guinea-pig were large numbers of GAL-IR fibers with a varicose appearance was observed. These fibers were in all species most numerous in the distal portion of the intestinal tract. In the submucosa GAL-IR fibers were detected in all four species, and in the pig and guinea-pig some fibers surrounded blood vessels. A large number of GAL-IR fibers was generally seen in the circular smooth muscle layer, except in the guinea-pig, which only seemed to contain a few fibers. In the longitudinal muscle layer only single fibers could be detected. However, the gastric fundus region of the pig contained a moderate number of fibers in the longitudinally and obliquely oriented layers.In general, in the rat, mouse and pig, the submucous and myenteric plexus contained moderate or large numbers of GAL-IR fibers. In the guinea-pig, no or only single fibers were observed in the plexus of the upper gastro-intestinal tract and the rectum, while moderate numbers were seen in the ileum and colon.Thin adjacent sections stained for vasoactive intestinal polypeptide (VIP) and GAL revealed the coexistence of these two peptides in cell bodies of the myenteric plexus in the pig duodenum and guinea-pig colon. In these two species the GALand VIP-nerve fiber networks also exhibited marked similarities. However, in the rat and mouse VIPand GAL-distribution patterns were in general different.The present findings indicate the presence of yet another neuropeptide or peptide family in the gastro-intestinal tract of several rodents and the pig.

Isolation of glucagon-37 (bioactive enteroglucagon/oxyntomodulin) from porcine jejuno-ileum Isolation of the peptide

A 37 amino acid‐peptide has been isolated from porcine jejuno‐ileum on the basis of its glucagon‐like activity in liver (interaction with glucagon‐binding sites and activation of adenylate cyclase) using gel filtration, ion‐exchange and high‐performance liquid chromatography. Depending on the criteria chosen, this peptide is referred to as either ‘bioactive enteroglucagon’ (activity in liver), ‘oxyntomodulin’ (specific action in gastric oxyntic glands) or ‘glucagon‐37’ (chemical structure).

Isolation of glucagon-37 (bioactive enteroglucagon/oxyntomodulin) from porcine jejuno-ileum

A peptide isolated from porcine gut according to its glucagon‐like activity in liver (bioactive enteroglucagon) has been characterized immunologically, biologically and chemically: its potency relative to pancreatic glucagon in interacting with an antiglucagon antibody, hepatic glucagon‐binding sites and hepatic adenylate cyclase was ∼100%, 20% and 10%, respectively. In contrast, it is ∼20‐times more potent than glucagon in oxyntic glands, justifying the term ‘oxyntomodulin’. Chemically, it consists in the 29 amino acid‐peptide glucagon elongated at its C‐terminal end by the octapeptide Lys—Arg—Asn—Lys—Asn—Asn—Ile &—Ala; accordingly, it is called ‘glucagon‐37’

Porcine peptide having N-terminal histidine and C-terminal isoleucine amide (PHI): Vasoactive intestinal peptide (VIP) and secretin-like effects in different tissues from the rat

We have suggested that the structurally related intestinal peptides vasoactive intestinal peptide (VIP) and secretin were effective on some of their target tissues through discrete binding sites coupled to a membrane-bound adenylate cyclase (EC 6.4.1 .I) [l-3]. In [4], we have shown that a novel peptide, the ‘porcine peptide having N-terminal histidine and C-terminal isoleucine amide’ (PHI) (formerly named PIHIA [4]), isolated from the porcine duodenum according to a specific chemical feature [5,6], possesses VIP-like activities. We have investigated in vitro the effect of PHI on cellular and plasma membrane preparations from the rat that are known to display either VIP-receptors (liver [l] and intestine [2]), secretin-receptors (stomach [3]), or both (fat [ 1,7]). The interest of this work was further supported by the recent observation that PHI possesses structural similarities with the peptides of the glucagon-VIPsecretin family [6]. We show here that, when tested on the production of 3’,5’-cyclic adenosine monophosphate (cyclic AMP), PHI was 20-40% as potent as VIP in tissue preparations that are primarily sensitive to VIP and 2-S% as potent as secretin in a preparation in which the latter peptide displays the predominant effect. In all cases, the effectiveness of PHI was correlated to the presence of either or both VIP (and secretin) receptors.

Characterization of an avian gastric (proventricular) peptide having sequence homology with the porcine gastrin-releasing peptide and the amphibian peptides bombesin and alytesin

Bombesin, a peptide with 14 amino acid residues, was isolated from the skin of an European frog [I ] and has been the subject of many recent investigations due to its diverse and potent pharmacological effects on the mammalian gastro-intestinal tract, pancreas, and central nervous system (reviewed [2,3]). We have reported the sequence of a 27 residue porcine gastrin-releas~g peptide (GRP) with marked C-terminal homology with bombesin [4]. Subsequent investigations indicate that natural porcine GRP and synthetic bombesin on intravenous administration, share the property of elevating plasma gastro-intestinalpancreatic hormone levels [Sf and that a synthetic replicate of GRP and bombesin on intracranial administration produce similar pharmacological effects [6]. Immunological evidence indicated that the avian proventriculus was an abundant source of bombesin-like immunoreactivity [7-91. We therefore began an investigation of extracts of the chicken proventriculus and report here the isolation and amino acid sequence of a 27 residue chicken proventricular peptide having marked sequence homology with the porcine GRP and the amphibian peprides bombesin and alytesin.