Dw. Schmidtke et al., MEASUREMENT AND MODELING OF THE TRANSIENT DIFFERENCE BETWEEN BLOOD AND SUBCUTANEOUS GLUCOSE-CONCENTRATIONS IN THE RAT AFTER INJECTION OF INSULIN, Proceedings of the National Academy of Sciences of the United Statesof America, 95(1), 1998, pp. 294-299
The kinetics of the fall in subcutaneous fluid glucose concentration i
n anesthetized rats (n = 7) after intravenous injection of insulin (0.
5 units/kg) was studied by using 5 x 10(-4) cm(2) active area, <150-se
c 10-90% response time, amperometric glucose sensors, The onset of the
decline in the subcutaneous glucose concentration was delayed and sta
tistically different (P < 0.001) from that in blood (8.9 +/- 2.1 min v
s, 3.3 +/- 0.5 min), Similarly, the rate of drop in glucose concentrat
ion between 6 and 20 min after the insulin injection was different for
subcutaneous tissue (3.9 +/- 1.3 mg.dl(-1). min(-1)) and blood (6.8 /- 2.0 mg.dl(-1).min(-1)) (P = 0.003). The hypoglycemic nadir in subcu
taneous fluid occurred 24.5 +/- 6.8 min after that in the blood (P < 0
.001), A ''forward'' mass-transfer model, predicting the subcutaneous
glucose concentration from the blood glucose concentrations and an ''i
nverse'' model, predicting the blood glucose concentration from the su
bcutaneous glucose concentration were derived, By using an algorithm b
ased on the latter, the average discrepancy between the measured blood
glucose concentration and that estimated from the subcutaneous measur
ement through the entire 4-hr experiment was reduced from 22.9% to 11.
1% (P = 0.025). The maximum discrepancy during the 40-min period after
the injection of insulin was reduced from 84.1% to 29.3% (P = 0.006).