In vitro release of vasopressin and oxytocin from rat median eminence tissue

Joseph G. Verbalis, Ernest F. Baldwin, Oline Ronnekleiv, Alan G. Robinson

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Release of vasopressin (AVP) and oxytocin (OT) from rat median eminence and posterior pituitary tissue was studied in vitro by incubation in Krebs-56 m M KCl buffer. Both total tissue content and releasable pool of each hormone was measured in control rats, adrenalectomized rats and dexametliasone-treated rats. Adrenalectomy resulted in significantly increased release of AVP. but not OT, from median eminence tissue, whereas dexamethasone treatment failed to affect release of either hormone. Neither treatment had any effect on AVP or OT release from posterior pituitary tissue. Similarly, neither treatment caused any significant changes in total median eminence or posterior pituitary AVP and OT contents relative to controls, although dexamethasone-treated rats had a significantly lower posterior pituitary OT content than adrenalectomized rats. KCl-stimulated hormone release from median eminence tissue most likely represents an estimate of AVP and OT in zona externa terminals rather than in zona interna axons, because release was blocked by CoCl2 indicating calcium-dependeiU exocytosis. Immunohistochemicul staining of median eminence tissue correlated well with the results of in vitro hormone release, in that increased AVP staining in the zona externa of adrenalectomized rats was also the only significant change noted using this methodology. Since increased levels of releasable AVP in the median eminence probably reflects similarly increased AVP levels in the hypothalamo-hypophyseal portal vessels of adrenalectomized rats, these results support a potential physiologic role for median eminence AVP, but not OT, in the chronic stimulation of adrenocorticotropin hormone secretion following adrenalectomy.

Original languageEnglish (US)
Pages (from-to)481-488
Number of pages8
JournalNeuroendocrinology
Volume42
Issue number6
DOIs
StatePublished - 1986

Fingerprint

Median Eminence
Oxytocin
Vasopressins
Hormones
Herpes Zoster
Adrenalectomy
Dexamethasone
Staining and Labeling
In Vitro Techniques
Exocytosis
Adrenocorticotropic Hormone
Axons
Buffers
Calcium

Keywords

  • Adrenal insufficiency
  • Adrenocorticotropin hormone
  • Dexainethiisonc
  • Median eminence
  • Neurohypophysis
  • Oxytocin
  • Vasopressin

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism
  • Cellular and Molecular Neuroscience
  • Endocrine and Autonomic Systems
  • Neuroscience(all)

Cite this

In vitro release of vasopressin and oxytocin from rat median eminence tissue. / Verbalis, Joseph G.; Baldwin, Ernest F.; Ronnekleiv, Oline; Robinson, Alan G.

In: Neuroendocrinology, Vol. 42, No. 6, 1986, p. 481-488.

Research output: Contribution to journalArticle

Verbalis, Joseph G. ; Baldwin, Ernest F. ; Ronnekleiv, Oline ; Robinson, Alan G. / In vitro release of vasopressin and oxytocin from rat median eminence tissue. In: Neuroendocrinology. 1986 ; Vol. 42, No. 6. pp. 481-488.
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