Metabolic and hormonal effects of glucagon infusion in erythroblastotic infants

Abstract

10 or 50 μg glucagon was added to the bottle of donor blood, preserved with acid citrate and dextrose, used for exchange transfusion of erythroblastotic infants. The effects of the glucagon infusion on plasma glucose, insulin, growth hormone (GH), and glucagon were measured during the transfusion and for 60 minutes thereafter, and were compared with transfusions in which no addition was made to the donor blood. Both doses of glucagon produced similar effects: higher mean plasma glucose and insulin levels during the transfusion, but no significant change in plasma growth hormone levels. Transfusion with glucagon-enriched blood had no effect on the net balance of glucose or growth hormone, but caused a negative insulin balance twice as big as that occurring in the control group. At the end of the control transfusions the mean plasma glucagon was 248 pg/ml and this did not change significantly in the next 60 minutes. When 10 or 50 μg glucagon was added to the donor blood the end-transfusion mean plasma glucagon concentrations were 1302 and 3975 pg/ml, respectively. Glucagon disappeared rapidly from plasma for 5 to 10 minutes and then more slowly at the rate of 0·5 to 1·0 % per minute for the next 50 minutes. The range of glucose disappearance rates in the 60 minutes after transfusion (0·40-2·13 %/min) was similar in all three groups, but the infants receiving glucagon-enriched blood had higher blood glucose levels for a given glucose disappearance rate. In each group there was a highly significant negative correlation between the 60-minute plasma glucose level and the glucose disappearance rate. It is concluded that the addition of 10 or 50 μg glucagon to the bottle of donor blood used for exchange transfusion may have a protective effect against post-transfusion hypoglycaemia. Measurement of the blood glucose level 60 minutes after the transfusion has both diagnostic and prognostic value in detecting hypoglycaemia.