Galanin Inhibits Glucose-Induced Insulin Release in Vitro

Leonhardt, U.; Eg, Siegel; Köhler, H.; Barthel, M.; Tytko, A; Nebendahl, Klaus; Creutzfeldt, W.

doi:10.1055/s-2007-1009161

Cited by 27 publications

(8 citation statements)

References 5 publications

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“…In comparison to bovine Gal (bGal) and rGal, 7 and 4 residues are different, respectively. All amino acid substitutions are restricted to the C-terminal part of the molecule (positions [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Table 1 compares the sequences of hGal, rGal, pGal, and bGal.…”

Section: Discussionmentioning

confidence: 99%

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Isolation and primary structure of pituitary human galanin, a 30-residue nonamidated neuropeptide.

Schmidt

Kratzin

Eckart

et al. 1991

Proc. Natl. Acad. Sci. U.S.A.

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Galanin (Gal), a 29-amino acid C-terminally amidated neuropeptide, is widely distributed throughout the central and peripheral nervous system. The primary structures of rat and bovine Gals were derived from the cDNA sequences of their precursors. To elucidate the structure of human Gal (hGal), we extracted 280 postmortem pituitaries in trifluoroacetic acid and purified hGal binding activity, by three successive HPLC steps, to homogeneity based on a radioreceptor assay. The primary structure of hGal was determined by automatic Edman degradation to be Gly-Trp-Thr-Leu-AsnSer-Ala-Gly-Tyr-Leu-Leu-Gly-Pro-His-Ala-Val-Gly-Asn-HisArg-Ser-Phe-Ser-Asp-Lys-Asn-Gly-Leu-Thr-Ser-COOH. The structure was confirmed by plasma desorption time-of-flight mass spectrometry, revealing a mass of 3156.1. Compared to the 29-residue porcine, rat, and bovine Gals, hGal uniquely comprises 30 amino acids possessing an additional nonamidated serine residue as C terminus. The nonamidated carboxylic group at the C terminus was proven by synthesis of amidated and nonamidated hGal and by mass spectrometry after selective methylation of all free carboxylic groups. Synthetic hGal possesses full biological activity on isolated rat fundus muscle strips.

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Section: Discussionmentioning

confidence: 99%

“…However, tissue levels of hGal-like immunoreactivity, as measured with antisera raised against pGal, are considerably lower than tissue levels in pigs and rats, indicating sequence heterogeneity (4,6). Moreover, substantial controversy exists on the effect of Gal on insulin secretion being inhibitory (17)(18)(19) or stimulatory (20) in different species.…”

mentioning

confidence: 99%

Isolation and primary structure of pituitary human galanin, a 30-residue nonamidated neuropeptide.

Schmidt

Kratzin

Eckart

et al. 1991

Proc. Natl. Acad. Sci. U.S.A.

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“…De Weille et al (67) concluded that galanin activates the channel by interacting with a specific receptor located on the extracellular surface of the 3-cell by a mechanism that does not involve a soluble cytoplasmic messenger. In several other studies, galanin was found to inhibit insulin release (69,70). Although galanin can activate K + channels regulated by ATP, studies by Sharp et al (71) also suggest that galanin inhibits the insulin secretory mechanism at an additional site distal to the regulation of [Ca 2+ ]|.…”

Section: Atp-sensitive K + Channel In P-cells Channel Is Inactivatmentioning

confidence: 94%

Ion Channels and Insulin Secretion

et al. 1990

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We review the role of ion channels in regulating insulin secretion from pancreatic beta-cells. By controlling ion permeability, ion channels at the membrane play a major role in regulating both electrical activity and signal transduction in the beta-cell. A proximal step in the cascade of events required for stimulus-secretion coupling is the closure of ATP-sensitive K+ channels, resulting in cell depolarization. Of particular relevance is the finding that this channel is directly regulated by a metabolite of glucose, which is the primary insulin secretagogue. In addition, this channel, or a closely associated protein, contains the sulfonylurea-binding site. Another K+ channel, the Ca2(+)-activated K+ channel, may be involved in cell repolarization to create homeostasis. Voltage-dependent Ca2+ channels are activated by cell depolarization and regulate Ca2+ influx into the cell. By controlling cytosolic free-Ca2+ levels ([Ca2+]i), these channels play an important role in transducing the initial stimulus to the effector systems that modulate insulin secretion. The link between a rise in [Ca2+]i and the terminal event of exocytosis is the least-understood aspect of stimulus-secretion coupling. However, phosphorylation studies have identified substrate proteins that may correspond to those involved in smooth muscle contraction, suggesting an analogy in the processes of stimulus secretion and excitation contraction. The advent of new methodology, particularly the patch-clamp technique, has fostered a more detailed characterization of the beta-cell ion channels. Furthermore, biochemical and molecular approaches developed for the structural analysis of ion channels in other tissues can now be applied to the isolation and characterization of the beta-cell ion channels. This is of particular significance because there appear to be tissue-specific variations in the different types of ion channels. Given the importance of ion channels in cell physiology, a knowledge of the structure and properties of these channels in the beta-cell is required for understanding the abnormalities of insulin secretion that occur in non-insulin-dependent diabetes mellitus. Ultimately, these studies should also provide new therapeutic approaches to the treatment of this disease.

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“…Immunoreactivity for galanin has been localized in pancreatic nerves and also in a subset of islets (2,10,35,116,121). Galanin inhibits secretion of insulin (103,109,116,121,174) and somatostatin (7,20). Ahren et al (3) were the first to study the effect of galanin on pancreatic exocrine secretion in isolated rat pancreatic acinar cells.…”

Section: Pancreatic Hormones and Neuropeptidesmentioning

confidence: 99%

The islet-acinar axis of the pancreas: more than just insulin

Barreto

Carati

Toouli³

et al. 2010

American Journal of Physiology-Gastrointestinal and Liver Physi

106

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Although the role of the islets in the regulation of acinar cell function seemed a mystery to investigators who observed their dispersion among pancreatic acini, over time an appreciation for this intricate and unique structural arrangement has developed. The last three decades have witnessed a steadily growing understanding of the interrelationship of the endocrine and the exocrine pancreas. The islet innervation and vascular anatomy have been more fully characterized and provide an appropriate background for our current understanding. The interrelationship between the endocrine and exocrine pancreas is mediated by islet-derived hormones such as insulin and somatostatin, other humoral factors including pancreastatin and ghrelin, and also neurotransmitters (nitric oxide, peptide YY, substance P, and galanin) released by the nerves innervating the pancreas. Although considerable progress has been achieved, further work is required to fully delineate the complex interplay of the numerous mechanisms involved. This review aims to provide a comprehensive update of the current literature available, bringing together data gleaned from studies addressing the actions of individual hormones, humoral factors, and neurotransmitters on the regulation of amylase secretion from the acinar cell. This comprehensive view of the islet-acinar axis of the pancreas while acknowledging the dominant role played by insulin and somatostatin on exocrine secretion sheds light on the influence of the various neuropeptides on amylase secretion.

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Galanin Inhibits Glucose-Induced Insulin Release in Vitro

Cited by 27 publications

References 5 publications

Isolation and primary structure of pituitary human galanin, a 30-residue nonamidated neuropeptide.

Isolation and primary structure of pituitary human galanin, a 30-residue nonamidated neuropeptide.

Ion Channels and Insulin Secretion

The islet-acinar axis of the pancreas: more than just insulin

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