Endocrine and Gastrointestinal Action of Galanin

Abstract

apid advances in the field of peptide chemistry and gene technology have resulted in a burst of determinations about the molecular structures not only of regulatory peptides such as galanins (Gal) of various species but also of their precursors and receptors. Based on information about mature peptides and precursor structures, Gal-related peptides and other peptides with related amino acid sequences were synthesized. Certain specifically designed synthetic peptides have enabled the investigation of such questions as the molecular basis of receptor binding and the active role of peptides. 1 Synthetic replicates of Gal of various species and its precursor-related peptides provide us with important immunogens for producing region-specific antibodies. Specific antibodies against Gal or its precursor-related peptides demonstrate well the posttranslational biosynthetic processing in cells and identify steps in the metabolite pathway of the regulatory peptide in tissues and tissue fluids. 2,3 Exogenous administration of Gal has been shown to contract smooth muscle preparations 3-6 and to inhibit neurally induced smooth muscle contractility. Gal stimulates the release of growth hormone (GH), 7,8 prolactin, 9 and luteinizing hormone either from dispersed pituitary cells or at the hypothalamic level modulating dopamine, vasoactive intestinal polypeptide, (VIP), somatostatin, opioid, and GnRH release into the portal circulation 10-13 and inhibits insulin release. [14][15][16][17][18][19][20][21][22][23] In this review, we describe structure-function studies of the endocrine and gastrointestinal action of Gal. PEPTIDES AND ANTISERAPeptides. All peptides used in the study were synthesized by solid phase methodology with BOC-or Fmoc-strategy using an automated peptide synthesizer (model 430A, Applied Biosystems, or model 9050, Perseptive, USA). The crude peptide was purified by reverse-phase HPLC on a column of YMC-Pack D-ODS-5 (2.0 × 25.0 cm) using 0.01 N HCl/CH 3 CN. Purity of the peptides was assessed by analytic HPLC on a column of YMC

Distribution of galanin in bone and joint tissues

“…It modulates pituitary hormone secretion and regulates the release of neurotransmitters. It also modulates appetite and sexual behavior (Bedecs et al 1995;Yanaihara et al 1998;Zhang et al 1998).…”