Immunohistochemical Localization and Radioimmunoassay of Corticotropin-Releasing Factor in the Forebrain and Hypophysis of the Frog Rana ridibund - Université de La Réunion Access content directly
Journal Articles Neuroendocrinology Year : 2004

Immunohistochemical Localization and Radioimmunoassay of Corticotropin-Releasing Factor in the Forebrain and Hypophysis of the Frog Rana ridibund

Marie-Christine Tonon
  • Function : Author
Arlette Burlet
  • Function : Author
Marc Lauber
  • Function : Author
Sylvie Jégou
  • Function : Author
Laurence Gouteux
  • Function : Author
Nicholas Ling
  • Function : Author
Hubert Vaudry
  • Function : Author

Abstract

The distribution of immunoreactive corticotropin-releasing hormone (CRF) in the forebrain and pituitary of the frog Rana ridibunda was studied by means of specific radioimmunoassay and immunohistochemistry using the indirect immunofluorescence and the peroxidase-antiperoxidase techniques. Relatively high concentrations of CRF-like material were found in both chiasmatic and infundibular regions of the hypothalamus (352 ± 11 and 422 ± 36 pg, respectively). Large amounts of CRF were also found in neurointermediate lobe extracts. Standard curves of synthetic CRF and the dilution curves for hypothalamic or neurointermediate lobe extracts were parallel. After Sephadex G-75 gel filtration, CRF-like immunoreactivity eluted in a single peak, in the same position as synthetic ovine CRF. Reversed-phase high-performance liquid chromatography of the material purified on Sephadex G-75 revealed 5 components with CRF-like immunoreactivity. The major peak had a retention time of 22 min as compared to 25.4 min for ovine CRF and 36 min for rat CRF. The detection of CRF-like immunoreactivity in neurons was facilitated by colchicine pretreatment of the frogs. The great majority of the CRF-positive perikarya were seen in the ventral region of the preoptic nucleus. A few scattered perikarya were also observed in the dorsal preoptic nucleus and in the retrochiasmatic region. Immunoreactive fibers were found in the infundibular nucleus and in various extrahypothalamic zones. CRF-containing neurons were apparently distinct from mesotocinergic and vasotocinergic neurons. A large number of immunoreactive nerve fibers were observed in the median eminence in close contact with the capillaries of the pituitary portal plexus and in the neural lobe. A few CRF-positive fibers were detected in the intermediate lobe, whereas the distal lobe was totally negative. These results show that the diencephalon and pars intermedia-nervosa of the frog contain a peptide immunologically related to mammalian CRF.
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hal-01368990 , version 1 (20-09-2016)

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Marie-Christine Tonon, Arlette Burlet, Marc Lauber, Pascale Cuet, Sylvie Jégou, et al.. Immunohistochemical Localization and Radioimmunoassay of Corticotropin-Releasing Factor in the Forebrain and Hypophysis of the Frog Rana ridibund. Neuroendocrinology, 2004, 40 (2), ⟨10.1159/000124063⟩. ⟨hal-01368990⟩
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