title: Immunoreactive endothelin distribution in ocular tissues.
abstract: OBJECTIVE
  To study the distribution of the endothelins in the eye using ocular tissues of human, rat, and porcine origin.
  
  
  METHODS
  Extracts of ocular tissues were examined for immunoreactivity to endothelin 1 and 3 and pro-endothelin 1 using radioimmunoassay. Characterization of immunoreactivity was verified using high-performance liquid chromatography.
  
  
  RESULTS
  Immunoreactivity to endothelin 1 and endothelin 3 was found in all ocular tissues except the cornea, which contained no immunoreactivity to endothelin 3. Highest levels were found in the choroid, although species-related differences were present. Immunoreactivity to endothelin 3 was generally twofold to threefold higher than immunoreactivity to endothelin 1. The majority of endothelin-like-immunoreactivity in the retina was blood vessel-associated. High-pressure liquid chromatography (HPLC) confirmed that immunoreactive endothelin 1 and endothelin 3 in the tissue extracts eluted in identical positions to their respective standard synthetic peptides.
  
  
  CONCLUSIONS
  The endothelins are abundantly distributed in the eye. Endothelin 1 is present in its mature, 21 amino acid form, and only minimal amounts of the precursor pro-endothelin is found in ocular tissues. The wide distribution patterns point to complex roles for these peptides in blood vessel physiology and in such other functions as regulation of aqueous outflow, and in neurotransmission or modulation.
authors.affiliation: Department of Ophthalmology, Queen's University of Belfast, Ireland.
authors.forename: U
authors.initials: U
authors.lastname: Chakravarthy
authors.forename: A J
authors.initials: AJ
authors.lastname: Douglas
authors.forename: J R
authors.initials: JR
authors.lastname: Bailie
authors.forename: B
authors.initials: B
authors.lastname: McKibben
authors.forename: D B
authors.initials: DB
authors.lastname: Archer
mesh_terms: D000368:Aged; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D019332:Endothelin-1; D016232:Endothelins / Q000032:analysis*; D005123:Eye / Q000737:chemistry*; D005260:Female; D006801:Humans; D008297:Male; D011498:Protein Precursors / Q000032:analysis; D011863:Radioimmunoassay; D051381:Rats; D013045:Species Specificity; D013552:Swine
chemical_list: D019332:Endothelin-1; D016232:Endothelins; D011498:Protein Precursors; C093240:proendothelin 1