Avasthy N, Khokher M A, Taylor A M, Dandona P
Diabetologia. 1986 Jul;29(7):453-6. doi: 10.1007/BF00506538.
Since human immunoglobulins exert an insulin-like stimulatory effect on adipocyte lipogenesis at concentrations markedly lower than those found in vivo, and since human serum or plasma are only midly stimulatory, we predicted that human serum probably contains an inhibitor of adipocyte lipogenesis. Supernatant preparations, obtained from the precipitation of immunoglobulins from plasma in 2.5 mol/l ammonium sulphate, were extensively dialysed and tested for their activity on bioassay systems commonly used for measuring insulin. The supernatants produced a marked inhibition of basal and insulin- or IgG-stimulated lipogenesis and glucose oxidation by adipocytes at protein concentrations of 10 mg/l. The supernatants were further purified through ultrafiltration to demonstrate two main inhibitory fractions, 10 to 30 K and 30 to 50 K, which again produced marked inhibition of basal and insulin- or IgG-stimulated adipocyte lipogenesis and glucose oxidation. These fractions were then tested for basal and serum somatomedin-stimulated 35S sulphate uptake by porcine cartilage: both basal and serum somatomedin-stimulated 35S uptake were significantly inhibited (p less than 0.01). Therefore, normal human serum contains at least two peptides which are markedly inhibitory to glucose metabolism and insulin action on adipocytes and 35S transport and somatomedin action on cartilage.
由于人免疫球蛋白在浓度显著低于体内发现的浓度时，就对脂肪细胞脂肪生成发挥胰岛素样刺激作用，且由于人血清或血浆仅有中度刺激作用，我们推测人血清可能含有脂肪细胞脂肪生成的抑制剂。从血浆中用2.5摩尔/升硫酸铵沉淀免疫球蛋白得到的上清液制剂，经过广泛透析，并在常用于测量胰岛素的生物测定系统上测试其活性。这些上清液在蛋白质浓度为10毫克/升时，对脂肪细胞的基础以及胰岛素或IgG刺激的脂肪生成和葡萄糖氧化产生显著抑制作用。通过超滤进一步纯化这些上清液，以证明有两个主要抑制组分，10至30千道尔顿和30至50千道尔顿，它们再次对基础以及胰岛素或IgG刺激的脂肪细胞脂肪生成和葡萄糖氧化产生显著抑制作用。然后测试这些组分对猪软骨基础以及血清生长调节素刺激的35S硫酸盐摄取的影响：基础以及血清生长调节素刺激的35S摄取均受到显著抑制（p小于0.01）。因此，正常人血清至少含有两种对葡萄糖代谢、胰岛素对脂肪细胞的作用以及35S转运和生长调节素对软骨的作用具有显著抑制作用的肽。
