Regulation Mechanism of Na/K-transport in skeletal Msucle
| Project/Area Number |
61570042
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
General physiology
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| Research Institution | Shiga University of Medical Science |
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Principal Investigator |
KITASATO Hiroshi Shiga University of Medical Science, Professor, 医学部, 教授 (20079700)
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| Co-Investigator(Kenkyū-buntansha) |
OMATSU-KANBE Mariko Shiga University of Medical Science, Assistant, 医学部, 助手 (80161397)
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| Project Period (FY) |
1986 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1987: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1986: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | Na / K-transport / K-ATPase / ouabain / monensin / insulin / インシュリン / サポニン / K輸送 / Na,K-ATPase / Chloroquine |
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| Research Abstract |
Although the Na/K-transport in skeletal muscle has been known to be stimulated by insulin, the mechanism of stimulation is not throughly understood. To elucidate the muchanism, the density of [^3H] ouabain-binding sites and Na,K-ATPase activity of plasma membrane were examined. Frog(Rana catesbeiana) leg muscles were used for these experiments throughout . Muscles were loaded with [^3H] ouabain by incubating in a variety of test solutions containing [^3H] ouabain for one hour at room temperature. From competition experiment with cold ouabain, the amount of [^3H] ouabain specifically bound to the binding sites on plasma membrane was estimated to be 80 - 90% of the total [^3H] ouabain in muscle. The concentration of cold ouabain required to suppress the specific [^3H] ouabain-binding to one half was 1.2 x 10^<-6>M. The [^3H] ouabain in muscle increased 1.7 times when the muscle was incubate with insulin for one hour. Monensin (10^<-5>M) completely blocked the stimulating effect of insulin of [^3H] ouabain-binding.
The Na,K-ATPase activity of plasma membrane fraction prepared from insulin-exposed muscle was about two fold of the activity of that prepared from intact muscle. Incubating membrane fragment preparation with saponin (0.33mg/mg protein), the Na,K-ATPase activity increased two fold. The Na,K-ATPase activity of saponin-treated membrane preparation was completely suppressed by ouabain, indicating that the membrane vesicles became leaky. The finding that adding insulin to the saponintreated membrane preparation had no effect on the Na,K-ATPase activity of the preparation, supports the view that insulin does not elevate the activity of Na,K-ATPase molecules which have been already present in palsma membrane.
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Report
(2 results)
Research Products
(14 results)
