Elahi D, McAloon-Dyke M, Fukagawa N K, Sclater A L, Wong G A, Shannon R P, Minaker K L, Miles J M, Rubenstein A H, Vandepol C J
Division on Aging, Harvard Medical School, Charles A. Dana Research Institute, Brockton/West Roxbury Veterans Affairs Medical Center, Boston, Massachusetts 02215.
Am J Physiol. 1993 Dec;265(6 Pt 1):E831-8. doi: 10.1152/ajpendo.1993.265.6.E831.
To examine the effects of recombinant human (rh) insulin-like growth factor I (IGF-I), insulin, and saline on metabolic parameters, we studied 20 young nonobese healthy men. Euglycemic clamps with 240-min IGF-I infusions at two doses (49 and 33 pmol.kg-1 x min-1, n = 8 and 12 subjects) were performed and compared with hyperinsulinemic-euglycemic clamps (2.25 pmol.kg-1 x min-1, n = 9). Leucine and glucose kinetics were examined with L-[1-13C]leucine and [3-3H]glucose. Glucose rate of appearance (Ra) declined equivalently in the 49 pmol.kg-1.min-1 IGF-I and insulin clamps but remained at basal levels during the 33 pmol.kg-1 x min-1 IGF-I infusions. In contrast, Rd of glucose was increased by 176% in the 49 pmol.kg-1 x min-1 IGF-I and 78% in the 33 pmol.kg-1 x min-1 IGF-I infusions. Furthermore, to prevent hypoglycemia after the termination of both rhIGF-I infusions, it was necessary to infuse glucose for an additional 2-20 h. Ra of leucine was suppressed significantly by both IGF-I and insulin, whereas leucine oxidation was not affected by either hormone. Therefore, the rate of disappearance of leucine expressed as the difference between Ra and oxidation rates was significantly reduced in all clamps. In addition, IGF-I significantly suppressed beta-cell secretion without affecting the other glucoregulatory hormones. In contrast to insulin, IGF-I had no apparent effect on lipolysis, as measured by changes in nonesterified fatty acids.(ABSTRACT TRUNCATED AT 250 WORDS)
为研究重组人（rh）胰岛素样生长因子I（IGF-I）、胰岛素和生理盐水对代谢参数的影响，我们对20名年轻非肥胖健康男性进行了研究。进行了两剂量（49和33 pmol·kg⁻¹·min⁻¹，分别为8名和12名受试者）的240分钟IGF-I输注的正常血糖钳夹试验，并与高胰岛素正常血糖钳夹试验（2.25 pmol·kg⁻¹·min⁻¹，9名受试者）进行比较。用L-[1-¹³C]亮氨酸和[3-³H]葡萄糖检测亮氨酸和葡萄糖动力学。在49 pmol·kg⁻¹·min⁻¹ IGF-I和胰岛素钳夹试验中，葡萄糖出现率（Ra）同等下降，但在33 pmol·kg⁻¹·min⁻¹ IGF-I输注期间保持在基础水平。相比之下，在49 pmol·kg⁻¹·min⁻¹ IGF-I输注中葡萄糖代谢率（Rd）增加了176%，在33 pmol·kg⁻¹·min⁻¹ IGF-I输注中增加了78%。此外，为防止两种rhIGF-I输注结束后发生低血糖，有必要额外输注葡萄糖2 - 20小时。IGF-I和胰岛素均显著抑制亮氨酸的Ra，而亮氨酸氧化不受任何一种激素影响。因此，在所有钳夹试验中，以Ra与氧化率之差表示亮氨酸的消失率均显著降低。此外，IGF-I显著抑制β细胞分泌，而不影响其他血糖调节激素。与胰岛素不同，通过非酯化脂肪酸变化测定，IGF-I对脂肪分解无明显影响。（摘要截短于250字）
