Smith W J, Underwood L E, Keyes L, Clemmons D R
Department of Pediatrics, Frank Porter Child Development Center, University of North Carolina, Chapel Hill 27599, USA.
J Clin Endocrinol Metab. 1997 Dec;82(12):3982-8. doi: 10.1210/jcem.82.12.4452.
To determine whether peptides of the insulin-like growth factor (IGF) system might be useful indicators of nutritional adequacy in premature infants, we studied 50 premature (25-34 weeks gestation) infants prospectively to define the relationship between nutrient intake and serum concentrations of IGF-I, IGF-binding protein-2 (IGFBP-2), and IGFBP-3. Each infant was monitored for at least 2 weeks. Nutrient intake was quantified from daily logs; weight was determined daily, and measurements of IGF-I, IGFBP-2, and IGFBP-3 in serum were made twice weekly. Serum IGF-I correlated strongly with length of gestation, increasing 4.03 +/- 0.95 ng/mL for each additional week of gestation (P < 0.0001) and 0.36 +/- 0.07 ng/mL day each day since birth (P < 0.0001). A higher intake of calories increased IGF-I by 0.07 +/- 0.01 ng/mL for each calorie per kg ingested over the previous 3 days (P < 0.0001). IGF-I increased quadratically as protein intake increased. For each change of 1% in calories as protein squared, IGF-I increased 0.36 +/- 0.11 ng/mL (P < 0.0001). Serum IGFBP-3 concentrations also correlated with length of gestation, increasing 25.06 +/- 11.83 micrograms/L.wk (P = 0.035) and 4.14 +/- 1.33 micrograms/.day since birth (P = 0.003). Unlike IGF-I, variation in the amount of protein supplied did not change IGFBP-3. As calorie intake increased, IGFBP-3 increased by 0.54 +/- 0.17 microgram/L for each calorie per kg consumed over the previous 3 days (P = 0.0015). In contrast to IGF-I and IGFBP-3, IGFBP-2 declined as the length of gestation increased (56.12 +/- 16.92 ng/mL.week; P = 0.001) and with each additional day of life (7.57 +/- 2.44 ng/mL.day; P = 0.003). Dietary protein, the predominant regulator of IGFBP-2, caused a decrease of 33.22 +/- 9.00 ng/mL with each percent increase in dietary calories as protein (P < 0.0003). Calorie intake had less effect on IGFBP-2 than protein intake. These results indicate that each of the three peptides studied is regulated in premature infants by nutritional intake, and that their regulatory patterns are qualitatively similar to those observed in older individuals. Measurements of these peptides in premature infants may be useful indicators of nutritional status and adequacy of nutrient intake.
为了确定胰岛素样生长因子（IGF）系统的肽类是否可能是早产儿营养充足的有用指标，我们对50名早产（妊娠25 - 34周）婴儿进行了前瞻性研究，以确定营养摄入与血清IGF - I、IGF结合蛋白 - 2（IGFBP - 2）和IGFBP - 3浓度之间的关系。每名婴儿至少监测2周。从每日记录中量化营养摄入；每天测定体重，每周两次测定血清中的IGF - I、IGFBP - 2和IGFBP - 3。血清IGF - I与妊娠时长密切相关，妊娠每增加1周，IGF - I增加4.03±0.95 ng/mL（P < 0.0001），自出生后每天增加0.36±0.07 ng/mL（P < 0.0001）。每摄入超过前3天每千克体重1卡路里的热量，IGF - I增加0.07±0.01 ng/mL（P < 0.0001）。随着蛋白质摄入量增加，IGF - I呈二次方增加。每卡路里作为蛋白质平方每变化1%，IGF - I增加0.36±0.11 ng/mL（P < 0.0001）。血清IGFBP - 3浓度也与妊娠时长相关，妊娠每增加1周，IGFBP - 3增加25.06±11.83 μg/L·周（P = 0.035），自出生后每天增加4.14±1.33 μg/L·天（P = 0.003）。与IGF - I不同，提供的蛋白质数量变化并未改变IGFBP - 3。随着热量摄入增加，每摄入超过前3天每千克体重1卡路里的热量，IGFBP - 3增加0.54±0.17 μg/L（P = 0.0015）。与IGF - I和IGFBP - 3相反，IGFBP - 2随着妊娠时长增加而下降（56.12±16.92 ng/mL·周；P = 0.001），且随着出生后每一天的增加而下降（7.57±2.44 ng/mL·天；P = 0.003）。膳食蛋白质是IGFBP - 2的主要调节因子，随着膳食热量作为蛋白质每增加1%，IGFBP - 2下降33.22±9.00 ng/mL（P < 0.0003）。热量摄入对IGFBP - 2的影响小于蛋白质摄入。这些结果表明，所研究的三种肽类在早产儿中均受营养摄入调节，且它们的调节模式在质量上与在年长个体中观察到的相似。在早产儿中测量这些肽类可能是营养状况和营养摄入充足性的有用指标。
