Philipps A F, Dubin J W, Raye J R
Am J Obstet Gynecol. 1980 Mar 1;136(5):597-602. doi: 10.1016/0002-9378(80)91010-8.
Standardized rapid infusions of alanine were performed in six fetal lambs and three neonatal lambs to test the hypothesis that elevations of circulating amino acids may induce insulin secretion. Fetal insulin secretion was induced and exhibited a biphasic pattern with maximal elevation (61.8 +/- 18.5 microunits/ml) by 60 minutes of infusion. Alanine infusion was not associated with elevation of plasma glucose. Linear regression analysis delineated a significant relationship between steady state infusion concentrations of alanine and insulin (r = 0.70, p less than 0.01); the correlation was improved by adding glucose as an additional variable (r = 0.80). Alanine infusions into the neonatal lamb demonstrated a similar early pattern of secretion. Two combined glucose-alanine infusions were performed in two fetal lambs and demonstrated a significant effect on the timing of insulin release although no synergy could be demonstrated. Insulin secretion may be important in the modulation of fetal and neonatal amino acid utilization for fuel or protein accretion. Alanine-induced insulin secretion could have the effect of sparing alanine as a glucose precursor and would allow enhanced tissue uptake for transamination and protein synthesis.
对6只胎羊和3只新生羔羊进行了标准化的丙氨酸快速输注，以检验循环氨基酸升高可能诱导胰岛素分泌这一假设。诱导了胎羊胰岛素分泌，其呈现双相模式，输注60分钟时达到最大升高（61.8±18.5微单位/毫升）。丙氨酸输注与血糖升高无关。线性回归分析表明丙氨酸稳态输注浓度与胰岛素之间存在显著关系（r = 0.70，p < 0.01）；通过将葡萄糖作为额外变量加入，相关性得到改善（r = 0.80）。对新生羔羊进行丙氨酸输注显示出类似的早期分泌模式。对2只胎羊进行了两次葡萄糖 - 丙氨酸联合输注，尽管未显示出协同作用，但对胰岛素释放时间有显著影响。胰岛素分泌可能在调节胎儿和新生儿将氨基酸用于能量或蛋白质积累方面很重要。丙氨酸诱导的胰岛素分泌可能会使丙氨酸作为葡萄糖前体得以保留，并能增强组织对其的摄取用于转氨基作用和蛋白质合成。
