Colocalization of immunoreactive endothelin-1 and neurohypophysial hormones in the axons of the neural lobe of the rat pituitary.
The intracellular localization of immunoreactive endothelin (ET)-1, and its colocalization with vasopressin (VP) and oxytocin (OT) in the rat neural lobe were investigated by immunogold techniques using specific antisera raised against ET-1, VP, and OT. There were two types of axons: the first contained VP-immunolabeled neurosecretory granules, and the second contained OT-immunolabeled neurosecretory granules. A considerable number of the neurosecretory granules in both types of axon were immunolabeled with antibodies against ET-1, although the VP-immunolabeled granules were more heavily labeled with anti-ET-1 antiserum than OT-immunolabeled ones. Double immunogold labeling clearly demonstrated the intragranular colocalization of immunoreactions for ET-1 and VP and that of immunoreactions for ET-1 and OT. These results suggest that ET in the neural lobe may be released concomitantly with neurohypophysial hormones. Its biological significance remains to be elucidated.
Nakamura
S
S
Biological Laboratory, Kanagawa Dental College, Yokosuka, Japan.
Naruse
M
M
Naruse
K
K
Shioda
S
S
Nakai
Y
Y
Uemura
H
H
D000818:Animals; D001369:Axons / Q000648:ultrastructure*; D016232:Endothelins / Q000032:analysis*; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D016253:Microscopy, Immunoelectron / Q000379:methods; D010121:Oxytocin / Q000032:analysis*; D010904:Pituitary Gland, Posterior / Q000166:cytology* / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D014667:Vasopressins / Q000032:analysis*
D016232:Endothelins; D014667:Vasopressins; D010121:Oxytocin