Antibodies obtained by xenotransplantation of organ-cultured median eminence specifically recognize hypothalamic tanycytes.
Tanycytes are specialized ependymal cells lining the infundibular recess of the third ventricle of the cerebrum. Early and recent investigations involve tanycytes in the mechanism of gonadotropin-releasing hormone (GnRH) release to the portal blood. The present investigation was performed to obtain a specific immunological marker of tanycytes and to identify the compound(s) responsible for this labeling. After 30 days of organ culture, explants of bovine median eminence formed spherical structures mostly constituted by tanycytes. These tanycyte spheres were xenotransplanted to rats, and the antibodies raised by the host animals against the transplanted living tanycytes were used for immunochemical studies of the bovine and rat median eminence. This antiserum immunoreacted with two compounds of 60 kDa and 85 kDa present in extracts of bovine and rat median eminence. The individual immunoblotting analysis of rat medial basal hypothalami showed a decrease in the amount of the 85-kDa compound in castrated rats as compared to control rats processed at oestrus and dioestrus. The antiserum, labeled as anti-P85, when used for immunostaining of sections throughout the rat central nervous system, immunoreacted specifically with the hypothalamic tanycytes. Within tanycytes, P-85 immunoreactivity was exclusively present in the basal processes. It is suggested that the 85-kDa and 60-kDa compounds correspond to two novel proteins selectively expressed by tanycytes. The possibility that they are secretory proteins involved in GnRH release is discussed. Anti-P85 appears to be the first specific marker of hypothalamic tanycytes.
Blázquez
Juan Luis
JL
Departamento de Anatomía e Histología Humanas, Facultad de Medicina, Universidad de Salamanca, Salamanca, Spain.
Guerra
Montserrat
M
Pastor
Francisco
F
Peruzzo
Bruno
B
Amat
Pedro
P
Rodríguez
Esteban Martín
EM
D000818:Animals; D002417:Cattle; D005260:Female; D007031:Hypothalamus / Q000166:cytology* / Q000276:immunology* / Q000648:ultrastructure; D015151:Immunoblotting; D007150:Immunohistochemistry; D008297:Male; D008473:Median Eminence / Q000276:immunology* / Q000637:transplantation*; D008854:Microscopy, Electron; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009924:Organ Culture Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D014020:Tissue Extracts / Q000276:immunology; D014183:Transplantation, Heterologous / Q000276:immunology*; D014617:Vacuoles / Q000648:ultrastructure
D009419:Nerve Tissue Proteins; D014020:Tissue Extracts