Horm Metab Res 2005; 37(5): 290-296
DOI: 10.1055/s-2005-861473
Original Clinical
© Georg Thieme Verlag KG Stuttgart · New York

Heterogeneous Forms of Immunoreactive Galanin in Human Plasma; Higher Levels in Men than in Women

E.  Grenbäck1 , A.-L.  Hulting1 , E.  Bucht1
  • 1 Department of Molecular Medicine, Endocrine and Diabetes Unit, Karolinska Hospital, Stockholm, Sweden
Further Information

Publication History

Received 19 July 2004

Accepted after revision 2 December 2004

Publication Date:
22 June 2005 (online)

Abstract

Galanin, a neuropeptide, has important effects on hormone secretion from the hypothalamus and pituitary, and may also be involved in important biological processes such as pain, memory, and food intake. Yet, there is limited knowledge about how these processes are reflected by circulating galanin. To study the levels and molecular forms of galanin in the human circulation, plasma was analysed from 27 healthy subjects, 14 women and 13 men, using two extraction methods and a specific radioimmunoassay for human galanin. After extraction on Sep Pak C-18 columns, plasma galanin-like immunoreactivity (galanin-LI) in the healthy men was 6.3 ± 2.5 pmol/l (mean ± SD, n = 12), which was higher than in the women, 4.1 ± 1.5 pmol/l (n = 14, p = 0.010). A small increase in galanin-LI was seen with age in the women (r = 0.54, p < 0.05) but there was no significant difference between pre- and postmenopausal women. Galanin immunoreactivity after Sep Pak and immunoextraction correlated (r = 0.74, p < 0.001) the levels being higher after immunoextraction (p < 0.001). Gel chromatography disclosed heterogeneity of circulating galanin-LI with the majority eluting as homologs with a molecular weight higher than synthetic human galanin. Homologs smaller than galanin were also found. Sep Pak C-18 extraction eliminated the majority of the higher molecular forms. In conclusion, circulating galanin-LI was found to be higher in men and to be present mainly as molecular forms larger than synthetic galanin.

References

  • 1 Tatemoto K, Rökaeus Å, Jörnvall H, Mc Donald T J, Mutt V. Galanin - a novel biologically active peptide from porcine intestine.  FEBS Lett.. 1983;  164 124-128
  • 2 Rökaeus Å, Melander T, Hökfelt T, Lundberg J M, Tatemoto K, Carlquist M, Mutt V. A galanin-like peptide in the central nervous system and intestine of the rat.  Neurosci Lett. 1984;  47 161-166
  • 3 Skofitsch G, Jacobowitz D M. Immunohistochemical mapping of galanin-like neurons in the rat central nervous system.  Peptides. 1985;  6 509-546
  • 4 Vrontakis M E, Peden L M, Duckworth M L, Friesen H G. Isolation and characterization of a complementary DNA (galanin) clone from estrogen-induced pituitary tumor messenger RNA.  J Biol Chem. 1987;  262 16 755-16 758
  • 5 Kaplan L M, Gabriel S M, Koenig J L, Sunday M E, Spindel E R, Martin J B. et al . Galanin is an estrogen-inducible secretory product of the rat anterior pituitary.  Proc Natl Acad Sci USA. 1988;  85 7408-7442
  • 6 Hulting A L, Meister B, Grimelius L, Wersäll J, Änggård A, Hökfelt T. Production of galanin-like peptide by a human pituitary adenoma: immunohistochemical evidence.  Acta Physiol Scand. 1989;  137 561-562
  • 7 Vrontakis M E, Sano T, Kovacs K, Friesen H G. Presence of galanin-like immunoreactivity in non-tumorous corticotrophs and corticotroph adenomas of the human pituitary.  J Clin Endocrinol Metab. 1990;  70 747-751
  • 8 Bennet W M, Hill S F, Ghatei M A, Bloom S R. Galanin in the normal pituitary and brain and in pituitary adenomas.  J Endocrinol. 1991;  130 463-467
  • 9 Hsu D W, Hooi S C, Hedley-Whyte T, Strauss R M, Kaplan L M. Coexpression of galanin and adrenocorticotropic hormone in human pituitary and pituitary adenomas.  Am J Pathol. 1991;  138 897-909
  • 10 Grenbäck E, Bjellerup P, Wallerman E, Lundblad L, Änggård A, Ericson K, Åman K, Mandry M, Hökfelt T, Hulting A L. Galanin in pituitary adenomas.  Regul Pept. 2004;  117 127-139
  • 11 Rökaeus Å, Brownstein M J. Construction of a porcine adrenal medullary cDNA library and nucleotide sequence analysis of two clones encoding a galanin precursor.  Proc Natl Acad Sci USA. 1986;  83 6287-6291
  • 12 Bauer F E, Hacker G W, Terenghi G, Adrian T E, Polak J M, Bloom S R. Localization and molecular forms of galanin in human adrenals: elevated levels in pheochromocytomas.  J Clin Endocrinol Metab. 1986;  63 1372-1378
  • 13 Bersani M, Thim L, Rasmussen T N, Holst J J. Galanin and galanin extended at the N-terminus with seven and nine amino acids are produced in and secreted from the porcine adrenal medulla in almost equal amounts.  Endocrinology. 1991;  129 2693-2698
  • 14 Bauer F E, Adrian T E, Christofides N D, Ferri G L, Yanaihara N, Polak J M, Bloom S R. Distribution and molecular heterogeneity of galanin in human, pig, guinea pig, and rat gastrointestinal tracts.  Gastroenterology. 1986;  91 877-883
  • 15 Bauer F E, Ginsberg L, Venetikou M, MacKay D J, Burrin J M, Bloom S R. Growth hormone release in man induced by galanin, a new hypothalamic peptide.  Lancet. 1986;  2 192-194
  • 16 Wynick D, Hammond P J, Akinsaya K O, Bloom S R. Galanin regulates basal and oestrogen-stimulated lactotroph function.  Nature. 1993;  364 529-532
  • 17 Moore J P Jr, Morrison D G, Hyde J F. Galanin gene expression is increased in the anterior pituitary gland of the human growth hormone-releasing hormone transgenic mice.  Endocrinology. 1994;  134 2005-2010
  • 18 López F J, Merchenthaler I, Ching M, Wisniewski M G, Negro-Vilar A. Galanin: a hypothalamic-hypophysiotropic hormone modulating reproductive functions.  Proc Natl Acad Sci USA. 1991;  88 4508-4512
  • 19 Crawley J N. The role of galanin in feeding behaviour.  Neuropeptides. 1999;  33 369-375
  • 20 Kalra S P, Horvath T L. Neuroendocrine interactions between galanin, opioids, and neuropeptide Y in the control of reproduction and appetite. In: Hökfelt T, Bartfai T, Crawley J (eds) Galanin basic research discoveries and therapeutic implications. New York; NY Acad Sci 1998 863: 236-240
  • 21 Leibowitz S. Differential functions of hypothalamic galanin cell grows in the regulation of eating and body weight.  Ann NY Acad Sci. 1998;  863 206-220
  • 22 McDonald M P, Gleason T C, Robinson J K, Crawley J. Galanin inhibits performance on rodent memory tasks.  Ann NY Acad Sci. 1998;  863 305-322
  • 23 Ögren S O, Schött P A, Kehr J, Yoshitake T, Misane I, Mannström P. et al . Modulation of acetylcholine and serotonin transmission by galanin.  Ann NY Acad Sci. 1998;  863 342-363
  • 24 Xu X J, Hökfelt T, Bartfai T, Wiesenfeld-Hallin Z. Galanin and spinal nociceptive mechanisms: recent advances and therapeutic implications.  Neuropeptides. 2000;  34 137-147
  • 25 Bersani M, Johnsen A H, Højrup P, Dunning B E, Andreasen J J, Holst J J. Human galanin: primary structure and identification of two molecular forms.  FEBS Lett. 1991;  283 189-194
  • 26 Evans H, Shine J. Human galanin: molecular cloning reveals a unique structure.  Endocrinology. 1991;  129 1682-1684
  • 27 McKnight G L, Karlsen A E, Kowalyk S, Mathewes S L, Sheppard P O, O’Hara P J, Taborsky G J Jr. Sequence of human galanin and its inhibition of glucose-stimulated insulin secretion from RIN cells.  Diabetes. 1991;  41 82-87
  • 28 Schmidt W E, Kratzin H, Eckart K, Drevs D, Mundkowski G, Clemens A, Katsoulis S, Schafer H, Gallwitz B, Creutzfeld W. Isolation and primary structure of pituitary human galanin, a 30-residue nonamidated neuropeptide.  Proc Natl Acad Sci USA. 1991;  88 11 435-11 439
  • 29 Ceresini G, Morganti S, Rebecchi I, Solerte S B, Ghizzoni L, Ablondi F, Valenti G. Evaluation of the circadian profile of peripheral plasma galanin concentrations in normal subjects.  Life Sci. 2002;  70 2657-2664
  • 30 Legakis I N, Mantzoouridis T, Saramantis A, Phenekos C, Tzioras C, Mountokalakis T. Human galanin secretion is increased upon normal exercise test in middle-age individuals.  Endocr Res. 2000;  26 357-364
  • 31 Invitti C, Brunani A, Pasqualinotto L, Dubini A, Bendinelli P, Maroni P, Cavagnini F. Plasma galanin concentrations in obese, normal weight and anorectic women.  Int J Obes Relat Metab Disord. 1995;  19 347-349
  • 32 Baranowska B, Wasilewska-Dziubínska E, Radzikowska M, Plonowski A, Roguski K. Neuropeptide Y, galanin, and leptin release in obese women and in women with anorexia nervosa.  Metabolism. 1997;  46 1384-1389
  • 33 Baranowska B, Radzikowska M, Wasilewska-Dziubínska E, Roguski K, Polonowski A. Relationship among leptin, neuropeptide Y, and galanin in young women and in postmenopausal women.  Menopause. 2000;  7 149-155
  • 34 Milewicz A, Bidzinska B, Mikulski E, Demissie M, Tworowska U. Influence of obesity and menopausal status on serum leptin, cholecystokinin, galanin and neuropeptide Y levels.  Gynecol Endocrinol. 2000;  14 196-203
  • 35 Invitti C, Pecori Giraldi F, Dubini A, Monroi P, Losa M, Piccoletti R, Cavagnini F. Galanin is released by adrenocorticotropin-secreting pituitary adenomas in vivo and in vitro.  J Clin Endocrinol Metab. 1999;  4 1351-1356
  • 36 Harling H, Holst J J. Circulating galanin: origin, metabolism, and pharmacokinetics in anesthetized pigs.  Am J Physio. 1992;  262 (1pt1) E52-E57
  • 37 Bauer F E, Adrian T E, Yanaihara N, Polak J M, Bloom S R. Chromatographic evidence for high-molecular-mass galanin immunoreactivity in pig and cat adrenal glands.  FEBS Letters. 1986;  201 327-331
  • 38 Bedecs K, Langel Ü, Xu X J, Wiesenfeld-Hallin Z, Bartfai T. Biological activities of two endogenously occurring N-terminally extended forms of galanin in the rat spinal cord.  Eur J Pharmacol. 1994;  259 151-156
  • 39 Philippe C, Clerc N, Mazet B, Niel J P. Immunochemical study of galanin in the cat digestive and autonomic ganglia.  Peptides. 1996;  1 1331-1335
  • 40 Theodorsson E, Rugarn O. Radioimmunoassay for rat galanin: immunochemical and chromatographic characterization of immunoreactivity in tissue extracts.  Scand J Clin Lab Invest. 2000;  60 411-418
  • 41 Bucht E, Tørring O, Sjöberg H E. Gel chromatography of immunoextracted plasma calcitonin in response to the calcium clamp in healthy males.  Acta Endocrinologica. 1985;  110 421-428
  • 42 Schmidt W E, Siegel E G, Lamberts R, Gallwitz B, Creutzfeld W. Pancreastatin: Molecular and immunocytochemical characterization of a novel peptide in porcine and human tissues.  Endocrinology. 1988;  123 1395-1404
  • 43 Hohmann J G, Clifton D K, Steiner R A. Galanin. analysis of its coexpression in gonadotropin-releasing hormone and growth hormone-releasing hormone neurons.  Ann NY Acad Sci. 1998;  863 221-234
  • 44 Perumal P, Vrontakis M E. Transgenic mice over-expressing galanin exhibit pituitary adenomas and increased secretion of galanin, prolactin and growth hormone.  J Endocrinol. 2003;  179 145-154
  • 45 Ceresini G, Fabbo A, Freddi M, Maggion M, Reali N, Troglio G, Valenti G. Concomitant evaluation of plasma galanin and catecholamine levels during a cold pressor test in healthy human male and female subjects.  Horm Res. 1997;  48 268-273

E. Grenbäck

Dept. of Molecular Medicine · Endocrine and Diabetes Unit · Karolinska Hospital, S-17176 Stockholm, Sweden

Phone: 46 (8) 517 730 65

Fax: 46 (8) 517 730 96

Email: Eva.Grenback@karolinska.se