| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1995: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1994: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
One of important characteristics of insulin-like growth factors is that these growth factors generally binds to their specific binding proteins (IGFBPs) in the serum or the conditioned media of cultured cells. Six distinct species of IGFBPs have been purified and their cDNAs have also been cloned. From this background, the present study is undertaken to elucidate the mechanisms of modulation of IGF bioactivity by IGFBPs. At first, we tried to purify each IGFBP from the conditioned media of various cultured cells. Rat IGFBP-1 and IGFBP-2 were purified from the conditioned media of H4-II-E cells and BRL-3A cells by the combination of hydrophobic chromatography, anion-exchange chromatography and reverse phase HPLC (C4). In addition, we are purifying rat IGFBP-4 from B104s cells in the almost same way as other IGFBPs at present. As for IGFBP-3, IGFBP-5 or IGFBP-6, establishment of the CHO cell line transfected with the expression vectors containing IGFBP-3, IGFBP-5 or IGFBP-6 cDNA is undergoing. At the same time, we have succeeded to get specific antibodies against some of these IGFBPs. In the future, we will treat IGF-1-target cells with IGF-1 or des [1-3] IGF-1 in the presence of purified IGFBPs followed by measurement of IGF-1 bioactivity. From these results, biologic roles fo each endogenous or exogenous IGFBPs will be elucidated at molecular levels.
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