日本産イワナ属魚類に関する研究-II : ニッコウイワナの視床下部神経分泌系
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概要
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The anatomy and the seasonal secretory cycle of the hypothalamo-hypophysial neurosecretory system in the Japanese char, the Nikko-iwana, Salvelinus leucomaenis pluvius, were examined histologically. The results obtained were as follows. 1. Using Billensteins (1963) staining methods, the neurosecretory substances of the nucleus preopticus lateralis are stained differentially. The former is CH- or AFpositive and the latter is acid fuchsin, azocarmine and phloxine positive. 2. The blue or purple axonal tracts of the nucleus preopticus reach the more ventral part of the neurohypophysis, via the hypothalamus, and the secretory substance is stored in the digits that penetrate into the pars intermedia. On the other hand, the red axons are distributed in the more dorsal part of the neurohypophysis, and some are found near the proximal zone of the pars distails. 3. Although a picture of secretion in the nucleus preopticus is recognized throughout the year, the activity becomes more marked in the prespawning season, and decreases after spawning. It seems probable that the neurohormonal substance stored in the neurohypophysis plays a role in the ejection of gametes. 4. In adult fish that have gonad-stimulating cells in the adenohypophysis, the secretory phase of the nucleus lateralis tuberis is also recognized throughout the year. The activity of the nucleus is correlated with the increase in number of the gonadotrophs and ripeness of the gametes. The secretory substance may be concerned with control of the gonad-stimulationg cells.
著者
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本間 義治
Deparlment of Biology, Faculty of Science, Niigata University
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本間 義治
Department of Biology, Faculty of Science, Niigata University and Arai High School
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田村 栄光
Department of Biology, Faculty of Science, Niigata University and Arai High School