Mechanism of neuronal protection by adenosine in the fetus.

目的：本研究的目的是探讨小于胎龄胎儿血浆嘌呤代谢产物与乳酸浓度、血气和pH值之间的关系。研究设计：对34例妊娠31-35周的生长迟缓胎儿进行脐带穿刺，测定脐静脉血浆腺苷、次黄嘌呤浓度、血气、pH值和乳酸浓度。脐静脉血浆腺苷浓度与脐静脉P02和pH呈负相关，而脐静脉血浆次黄嘌呤浓度则显著升高，与酸中毒程度平行（r=-0.74，p<0.05）和碱缺乏（r=-0.41，p <0.05），但与低氧血症程度及其他测量变量无显著相关性。我们推测，在胎儿窒息时，血浆腺苷水平的升高作为一种应激反应而引起保护性适应，而血浆次黄嘌呤浓度的升高可能反映了分娩前生长迟缓胎儿的生理状态受损。

OBJECTIVE : Our purpose in this study was to investigate the relationship between fetal plasma purine metabolites and lactate concentrations, blood gases, and pH in small-for- gestational-age fetuses.STUDY DESIGN : Cordocentesis was performed in 34 growth-retarded fetuses at 31-35 week's gestation for measuremwnt of umbilical venous plasma concentrations of adenosine, hypoxanthine, blood gases, pH and lactate concentrations.RESULTS : Umbilical venous plasma adenosine concentration was inversely related to umbilical venous P02 and pH, while umbilical venous plasma concentrations of hypoxanthine was found to be increased significantly, in parallel with the degree of acidosis (r=-O.74, p<O.05) and base deficit (r=-O.41, p<O.05), but not to be bear a significant relationship to the degree of hypoxemia or other measured variables.CONCLUSION : We posturate that the acompanying elevation of plasma adenosine elicits protective adaptation during fetal asphyxia as a stress response while increases in the plasma concentration of hypoxanthine may reflect an impaired physiological state in growth -retarded fetuses before labor.