title: Effects of 17β-estradiol on galanin(1-29)- and galanin(1-16)-like immunoreactivities.
abstract: There are reasons to believe that the galanin neuropeptide family could include more than the two hitherto known members (galanin(1-29) and galanin-like peptide), such as the existence of at least three galanin receptors and the fact that synthetic short-chain homologues have effects and binding sites that are distinct from those of galanin(1-29). The current study uses a radioimmunoassay based on a polyclonal rabbit antiserum raised against galanin(1-16) to study the concentrations of galanin(1-16) like immunoreactivity (LI) in the various parts of the brain and gut of ovariectomized female rats, and investigates the effects of different concentrations of estradiol on these concentrations in relation to galanin(1-29)-LI. Galanin(1-29) concentrations were increased by 17β-estradiol administration in almost all examined tissues whereas galanin(1-16)-LI was increased by 17β-estradiol treatment in most of the gut, but only in the pituitary of the brain. Furthermore, the relation between galanin(1-29)-LI and galanin(1-16)-LI varied substantially from tissue to tissue. The main hypothesis, that galanin(1-16)-LI would be affected by 17β-estradiol in brain and/or gut, was confirmed in addition to the secondary hypothesis, stating that the pattern of galanin(1-16)-LI changes would differ from that of galanin(1-29). The study indicates that galanin(1-16)-LI is estrogen-responsive but that its concentrations are regulated differently from that of galanin(1-29). This is strongly indicative of a biological relevance of this potentially new member of the galanin neuropeptide family.
authors: Clinical Chemistry, Department of Clinical and Experimental Medicine, Faculty of Health Sciences, Linköping University, Linköping, Sweden. jakob.strom@liu.se
authors: Jakob O
authors: JO
authors: Strom
authors: Tove
authors: T
authors: Nilsson
authors: Elvar
authors: E
authors: Theodorsson
mesh_terms: D000818:Animals; D001921:Brain; D002851:Chromatography, High Pressure Liquid; D004958:Estradiol / Q000097:blood / Q000494:pharmacology*; D005260:Female; D044089:Galanin-Like Peptide / Q000276:immunology*; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D012044:Regression Analysis; D014018:Tissue Distribution
chemical_list: D044089:Galanin-Like Peptide; D004958:Estradiol