| Budget Amount *help |
¥3,020,000 (Direct Cost: ¥2,600,000、Indirect Cost: ¥420,000)
Fiscal Year 2011: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2010: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
It has been revealed that there have been anti-insulin natural auto anti-insulin antibodies in serum of cats, and those were the IgG. To clarify the significance of anti-insulin IgGs, we developed a sandwich ELISA for determination of the IgGs in serum of cats. The accuracy of the ELISA was sufficient for determination of insulin-bound IgG concentrations. By used of this ELISA, we determined plasma anti-insulin IgG concentrations in 130 domestic cats and 11 other felidae(lions, leopards, snow leopards, bobcats and lynx). Anti-insulin IgGs were detected in ranges from 80 to 4, 884μg/ml in all individuals. Anti-insulin IgG concentrations were high in lean cats, and correlated positively with total IgG concentrations, but not with plasma glucose and insulin concentrations. In cats with diabetes mellitus, plasma anti-insulin IgG concentrations were slightly high, but within the range of normal cats. Anti-insulin IgGs were not detected in cord blood of newborn kittens, and increased after suckling. These maternal antibodies decreased gradually during suckling period, and reversed the falling trend at weaning.
Anti-insulin IgGs were fractionated by affinity chromatography with a column fixed bovine insulin. Epitope mapping was carried out by use of partial peptides of bovine insulin. The antigen-recognition parts were extrapolated hydrophilic terminals of A and B chains of insulin molecule.
Serum anti-insulin IgGs were divided into 4 fractions by high performance liquid chromatography. By use of a fraction with highest peak, we detected a phosphorylated tyrosine proteins in cultured adipocytes derived from the cat. The phospholylation was stronger after addition of the IgG-binding insulin than free insulin, suggesting that the anti-insulin IgG might enhance the action of insulin.
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