Douglas R G, Breier B H, Gallaher B W, Koea J B, Shaw J H, Gluckman P D
Department of Paediatrics, University of Auckland, New Zealand.
Diabetologia. 1991 Nov;34(11):790-5. doi: 10.1007/BF00408352.
We have investigated the relationship between the plasma distribution of infused recombinant insulin-like growth factor-I across the insulin-like growth factor binding proteins and the resultant effects on glucose and fat metabolism. The studies were performed in 24-h fasted ram lambs which received primed constant infusions of 3H labelled glucose tracer. When isotopic equilibrium had been reached, the animals received 90-min infusions of human insulin-like growth factor-I at various doses (2.5, 20, 40 and 120 micrograms.kg-1.h-1, n = 3 for each dose). Total plasma insulin-like growth factor-I was significantly elevated by infusion at a rate of 40 micrograms.kg-1.h-1 (from 185 +/- 14 micrograms/l to 442 +/- 41 micrograms/l, p less than 0.05) and 120 micrograms.kg-1.h-1 (from 181 +/- 2 micrograms/l to 953 +/- 39 micrograms/l, p less than 0.005). The plasma concentrations of insulin-like growth factor-I not associated with binding proteins remained undetectable (less than 15 micrograms/l) at the end of the 2.5 and 20 micrograms.kg-1.h-1 doses, but were significantly elevated at the end of the 40 and 120 micrograms.kg-1.h-1 infusions (to 71 +/- 14 micrograms/l, p less than 0.05 and 176 +/- 55 micrograms/l, p less than 0.01 respectively). The infused insulin-like growth factor-I associated primarily with 35-60 kilodalton binding proteins. Glucose kinetics were significantly altered only by the highest dose infusion, during which there was a fall in plasma glucose concentration from 3.5 +/- 0.2 mmol/l to 1.9 +/- 0.2 mmol/l (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
我们研究了注入的重组胰岛素样生长因子-I在胰岛素样生长因子结合蛋白间的血浆分布情况，以及由此对葡萄糖和脂肪代谢产生的影响。研究在禁食24小时的雄性羔羊身上进行，这些羔羊接受了用³H标记的葡萄糖示踪剂的首剂恒速输注。当达到同位素平衡后，动物接受了90分钟不同剂量（2.5、20、40和120微克·千克⁻¹·小时⁻¹，每个剂量n = 3）的人胰岛素样生长因子-I输注。以40微克·千克⁻¹·小时⁻¹（从185 ± 14微克/升升至442 ± 41微克/升，p < 0.05）和120微克·千克⁻¹·小时⁻¹（从181 ± 2微克/升升至953 ± 39微克/升，p < 0.005）的速率输注时，总血浆胰岛素样生长因子-I显著升高。在2.5和20微克·千克⁻¹·小时⁻¹剂量结束时，与结合蛋白不相关的胰岛素样生长因子-I的血浆浓度仍检测不到（低于15微克/升），但在40和120微克·千克⁻¹·小时⁻¹输注结束时显著升高（分别升至71 ± 14微克/升，p < 0.05和176 ± 55微克/升，p < 0.01）。注入的胰岛素样生长因子-I主要与35 - 60千道尔顿的结合蛋白结合。仅最高剂量输注显著改变了葡萄糖动力学，在此期间血浆葡萄糖浓度从3.5 ± 0.2毫摩尔/升降至1.9 ± 0.2毫摩尔/升（p < 0.05）。（摘要截选至250词）
