PLASMA AND CEREBROSPINAL-FLUID HYPERINSULINISM IN ASPHYXIATED PIGLETS

Insulin (I) plays a crucial role in the maturation of the perinatal br ain, and it may also be involved in the pathogenesis of neonatal brain injuries. The aim of the present study was to reveal the effect of ne onatal asphyxia on the regulation of I and glucose (G) metabolism in p lasma and cerebrospinal fluid (CSF) in newborn piglets. The I concentr ations were measured by radioimmunoassay, while the G levels were anal yzed by the G oxidase method during three phases (basal, critical, rec overy) of bilateral pneumothorax in newborn piglets. We observed a sig nificant hyperinsulinism (p < 0.001) both in plasma and CSF and a mild hypoglycemia (p < 0.05) during the recovery period. Postasphyxial G i nfusion (1.1 M, 10 ml . kg(-1)) amplified the hyperinsulinism. The I-C SF/plasma ratio (mean +/- SEM; n = 16) was decreasing during cardiovas cular failure (0.09 +/- 0.02; NS) as compared with the initial value ( 0.12 +/- 0.04), then it returned to basal values by 60 min (0.14 +/- 0 .04; NS), and increased significantly 180 min (0.40 +/- 0.14; p < 0.05 ) after resuscitation of the piglets. There was a similar increase in G(CSF/plasma) ratio in asphyxiated animals at the end of experiments ( 0.99 +/- 0.15 vs. initial 0.76 +/- 0.05; p < 0.05). In conclusion, neo natal asphyxia resulted in plasma and CSF hyperinsulinism which may al ter hypoxic-ischemic cerebral damages.