1997 Fiscal Year Final Research Report Summary
Studies on the influence of nutrition on the rate of protein synthesis and insulin-like growth factor-I in the chicken
| Project/Area Number |
08456140
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied animal science
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| Research Institution | Nagoya University |
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Principal Investigator |
OKUMURA Jun-ichi Nagoya University, Professor, 農学部, 教授 (10023425)
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| Co-Investigator(Kenkyū-buntansha) |
KITA Kazumi Nagoya University, Assistant Professor, 農学部, 助手 (20221913)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Chicken / Protein synthesis / Insulin-like growth factor-I / Muscle / Liver / Protein / Carbohydrate / Fat |
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| Research Abstract |
It has been reported that refeeding rapidly increases protein synthesis in fasted chickens and that plasma insulin-like growth factor-I (IGF-I) concentration is also very sensitive to the alteration in nutritional status. In the present study, we investigated the relationship of plasma IGF-I concentration and hepatic IGF-I mRNA level to the rate of tissue protein synthesis under various nutritional conditions. The rate of tissue protein synthesis was measured by a large dose injection of [^3H]-phenylalanine. Plasma IGF-I concentration was measured by radioimmunoassay. Hepatic IGF-I mRNA was quantified by ribonuclease protection assay. Plasma IGF-I concentration increased from 1 to 6 weeks of age, and the reduction of plasma IGF-I concentration was observed in fasted chicks. Both muscle protein synthesis and hepatic IGF-I mRNA level were decreased by 1-day fasting in 1-and 2-week-old chicks, and the amount of protein synthesized in muscles positively correlated to the change in hepatic IGF-I mRNA levels. On 15 days of age, chicks were fasted for 2 days and then refed with the combination of protein, carbohydrate and fat. After 30 minutes of refeeding the rates of muscle and liver protein synthesis and plasma IGF-I concentration were measured. No interaction of refeeding of various nutrients was observed in liver and muscle protein synthesis. The rate of protein synthesis, which has been decreased by fasting, was increased by individual nutrient refeeding. Plasma IGF-I concentration was decreased by fasting, and no change was observed in plasma IGF-I after 30 minutes of refeeding with various nutrients. These results suggested that acute increase in muscle protein synthesis by refeeding in fasted chicks is not associated to the change in plasma IGF-I concentration.
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