The hypothalamo-neurohypophysial system in Indian fresh-water goby, Glossogobius giuris (Ham.).

The hypothalamo-neurohypophysial neurosecretory system in Indian fresh-water goby, Glossogobius giuris (Ham.) has been described. The tractus preoptico-hypophyseus serves the function of a morphological and physiological connection between the hypothalamus and pituitary gland. In addition to main mass of the nucleus preopticus cells (cystine/cysteine bearing), a group of few cells in the hypothalamus has also been observed. These cells are situated posterior to the position of the nucleus preopricus and are CH Ph + ve and AF + ve. The neurosecretory material in the cells of nucleus preopticus is in the form of fine granules. The nucleus lateralis tuberis is absent in the fish under study. The disposition of neurosecretory material is heaviest along the fibres of the neurohypophysis in the region of pars intermedia with which it forms a profuse interdigitation. The fibres usually terminate over the blood vessels. The Herring bodies are noticeable at different levels in the neurohypophysis and pars-distalis. Besides the neurosecretory fibres, Herring bodies, non-stainableneurosecretory fibres and blood vessels, the pituicytes are also present in the neurohypophysis (SAKSENA 1974a, b). The intraaxonal flow of neurosecretory material, the vascularization of the nucleus preopticus and hypothalamo-hypophysial regulatory mechanism have been also discussed.