| Co-Investigator(Kenkyū-buntansha) |
SONODA Tatsunobu Miyazaki University, Agriculture, Professor, 農学部, 教授 (00040866)
YAMAUCHI Kiyoshi Miyazaki University, Agriculture, Professor, 農学部, 教授 (90040865)
SUIKO Masahito Miyazaki University, Agriculture, Ass. Prof., 農学部, 助教授 (00128357)
SATO Shusuke Miyazaki University, Agriculture, Ass. Prof., 農学部, 助教授 (80136796)
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| Research Abstract |
In order to apply newly-characterized endogenous appetite modifiers to the domestic animals, their existences and variation in the blood of animals, the effects of their administration on food intake, behavior and some physiological functions, and their mechanisms were investigated.
The existence of 2B40 (2-buten-4-olide) in animals was confirmed by the gaschromatogram of their plsma. The concentration was the highest in sheep, nextly in cattle, and also higher in pig than in chickens and rats. It was increased after feeding and decreased after fasting, during which the lowered level was kept for 120 hrs in ruminants.
Peripheral administration of 2B40 in sheep suppressed eating and also rumination. 2B40 administration in chickens suppressed eating dose-dependently, even if orally, and it also induced hypothermia and suppressed the gastric movement.
Hypothermia by 2B40 was due to trancient acceleration of heat loss and chronic inhibition of heat production, which was confirmed using a calo
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rimeter. This phenomenon was shown to be attributed to let-down of the set-point for controlling body temperature. Microinjection of 2B40 into the hypothalamic heat loss center induced a slight hyperthermia, and the injection into the heat production center induced severe hypothermia. On the other hand, the central neurochemical mechanism of this hypothermia was surveyed using the blockers to H1, H2 and 5HT receptors. Results were not obtained to in dicate that the hypothermia was induced via these receptor mechanisms.
When 245TP (2, 4, 5-trihydroxy pentanoic acid gamma-lactone) of the same dose to rats was given to chickens peripherally, no clear acceleration of food intake was seen. But microinjection of 245TP into the lateral hypothalamic area accelerated appetite and their food intake was twiced. the existence of this substance was confirmed by the gaschromatogram of chicken's plasma.
In conclusion, 2B40 and 245TP were confirmed to be endogenous appetite modifiers in the domestic animals. Less
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