Insulin induced hypoglycaemia: comparison of glucose and glycerol concentrations in plasma and microdialysate from subcutaneous adipose tissue

AIMS—To investigate the dynamics between plasmaand dialysate glucose during hypoglycaemia in children.
STUDY DESIGN—Six children in prepuberty or earlypuberty were investigated by multiple blood sampling and microdialysisof subcutaneous adipose tissue during a standard arginine-insulintolerance test. Glucose and glycerol, as an index of lipolysis, weremeasured in samples from both compartments. Plasma concentrations ofinsulin and the main counterregulatory hormones were also measured.
RESULTS—Plasma and dialysate glucoseconcentrations were very similar at baseline and increased in concertafter infusion of arginine, probably in response to glucagon release.After insulin injection, glucose in both plasma and dialysate fell inparallel. The subsequent hypoglycaemic stress response induced a rapidrebound in the plasma concentration with a mean (SD) delay in thedialysate of 16 (3) minutes. Plasma glycerol was approximately fivefoldlower than in the dialysate and did not fluctuate significantly.Dialysate glycerol decreased with arginine infusion and reached a nadir immediately following insulin administration. Subsequently, the antilipolytic effect of insulin was overcome by the hypoglycaemic stress response, and lipolysis prevailed in spite of hyperinsulinaemia.
CONCLUSION—After rapidly inducedhypoglycaemia, rebound of interstitial glucose concentrations issignificantly delayed compared with plasma concentrations, and theantilipolytic effect of hyperinsulinaemia is opposed possibly by thehypoglycaemic stress response.