Melatonin Receptors on Ovine Pars Tuberalis: Characterization and Autoradiographicai Localization

Peter John Morgan, Lynda Williams, G DAVIDSON, W LAWSON, E HOWELL

Research output: Contribution to journalComment/debatepeer-review

168 Citations (Scopus)


The functional significance of the pars tuberalis (PT) of the mammalian adenohypophysis has remained an enigma (1, 2). One view of its function is that it acts as an auxiliary gland to support the endocrine role of the pars distalis (PD) (2), as it has been shown to contain immunocytochemically identifiable thyrotrophs and gonadotrophs (1). Many of the cells of the PT are, however, ultrastructurally unique suggesting an independent function for this tissue. Our recent demonstration that the PT of the rat is a major binding site for the ligand iodomelatonin lends further support to this idea (3). We have utilized the highly specific ligand [125l]melatonin, and have demonstrated that it binds exclusively, with very high affinity, to the PT but not the PD of the adult sheep adenohypophysis. These findings support the conclusion that the PT has a distinct role in relation to melatonin action and seasonal reproduction.

Original languageEnglish
Pages (from-to)14
Number of pages4
JournalJournal of Neuroendocrinology
Issue number1
Publication statusPublished - Feb 1989


  • melatonin receptors
  • sheep
  • pars tuberalis
  • autoradiographical localization
  • characterization


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