젖소 초유 유청을 ulafiltration으로서 30kDa와 1kDa 사이의 IGF-Ⅰ rich fraction을 분획하였다. 분획한 IGF-Ⅰ rich fraction은 SDS-PAGE와 Western blotting으로 IGF-Ⅰ이 존재하는 것을 확인하였고, sandwich ELISA로써 그 함량을 측정한 결과 fraction중 IGF-Ⅰ의 함량은 단백질 mg당 10 ng으로 나타났다. IGF- I rich fraction으로 IEC-6, Detroit 551, EL-4 및 L6 in vitro 세포의 증식에 미치는 효과를 실험한 결과 IEC-6 cell은 IGF-Ⅰ 기준으로 10 ng, 1 ng, 0.1 ng, 0.01 ng에서 각각 대조구에 비해서 60%, 53%, 30%, 그리고 20군의 세포중식효과를 나타내었다. IEC-6의 증식은 IGF-Ⅰ의 투여량이 증가할수록 세포의 증식효과가 더 높게 나타났다. Detroit 551 cell은 10 ng과 1 ng수준에서 각각 56%와 26%의 세포증식 효과를 나타내었다. 그리고 EL-4 cell과 L6 cell은 10 ng 수준에서 각각 53%와 46%의 세포증식 효과를 나타내었다. 모든 세포주에서 IGF-Ⅰ함유농도가 10 ng 투여구에서 세포 증식율이 가장 높았으며 IEC-6 cell, Detroit 551 및 EL-4 cell은 모두 약60%의 세포 성장률을 나타내었고 L6 cell은 약 50%의 성장률을 보였다.

Insulin-like growth factor-I (IGF-Ⅰ) rich fraction, which was obtained molecules ranged between 30kDa and 1kDa, was fractionated by ultrafiltration from bovine colostral whey with 30kDa and 1kDa membrane. IGF-Ⅰ included in fractionated IGF-Ⅰ rich fraction was confirmed by SDS-PAGE and western blotting and then the quantity of IGF-Ⅰ was measured by ELISA. IGF-Ⅰ concentration in IGF-Ⅰ rich fraction was 10ng/mg protein. Effect of IGF-Ⅰ rich fraction on in vitro proliferation of several cells was tested. IEC-6 cell proliferation rate was increased 60%. 53%, 30%, and 20% at 10ng, 1ng, 0.lng, and 0.01ng of IGF-Ⅰ, respectively, compared to control group which was not supplemented by IGF-Ⅰ rich fraction. IGF-Ⅰ rich fraction stimulated in vitro proliferation of IEC-6 cell in a dose dependent manner by increasing cell number. Detroit 551 cell proliferation was enhanced 56% and 26% at 10ng and 1ng level of IGF-Ⅰ, respectively, compared to control group. EL-4 cell and L6 cell proliferation was increased 53% and 46% at 10ng of IGF-Ⅰ, respectively, compared to control group.