文摘
The development of a hypoglycemic alarm system usinga subcutaneous glucose sensor implies that a decreasein blood glucose is rapidly followed by a decrease in thesignal generated by the sensor. In a first set ofexperiments, the linearity and the kinetics of the response ofsensors implanted in the subcutaneous tissue of normalrats were investigated during a progressive increase inplasma glucose concentration: the sensitivities determined between 5 and 10 mM and between 10 and 15mM were not significantly different, and a 5-10 mindelayin the sensor's response was observed. In a secondsetof experiments, performed in diabetic rats, the kineticsof the decrease in subcutaneous glucose concentrationfollowing insulin administration was monitored during adecrease in plasma glucose level, from 15 to 3 mmol/L.During the 20 first min following insulinadministration,the sensor monitored glucose concentration in subcutaneous tissue with no lag time. Subsequently, thedecreasein the estimation of subcutaneous glucose concentrationpreceded that of plasma glucose. This phenomenon wasnot observed when the same sensors were investigatedin vitro during a similar decrease in glucoseconcentrationand may be due to a mechanism occurring in vivo, suchas the effect of insulin on glucose transfer from theinterstitial space to the cells surrounding the sensor.Itreinforces the interest of the use of implantable glucosesensors as a part of a hypoglycemic alarm.