Secretion Masses in the Nuclei of the Caudal Neurosecretory Cells of the Teleost Albula vulpes

Abstract

‘NUCLEAR secretion’ has been reported by a number of students of neurosecretory cells, especially in fish hypothalamic neurones^1–7. Neurones exhibiting similar characteristics have been described in the caudal neurosecretory system of two isospondylous teleosts: Albula vulpes and Elops hawaiensis^8,9. The caudal neurones of many teleosts may possess various kinds of nuclear inclusions, generally less prominent than those of Albula and Elops, and not necessarily considered as ‘secretion’^10–12. Inasmuch as the actual production of proteinaceous secretory product within the nucleus is not consonant with the present conception of the protein-secretory cell, we undertook a re-examination of the caudal neurosecretory neurones in Albula vulpes, the Hawaiian ‘oio’ or bonefish, with the electron microscope.