Kinetics of glucose delivery to subcutaneous tissue in rats measured with 0.3-mm amperometric microsensors

The time between i.v. injection of a glucose bolus and the time the glucose concn. peaked in the s.c. tissue was measured in pentobarbital-anesthetized rats with implanted 290-mm-diam. amperometric sensors. Boluses of 100, 200, and 400 mg/kg body wt. were injected. The glucose concn. in the jugular vein was monitored by frequent withdrawal and anal. of samples. The glucose concn. in the s.c. tissue was continuously monitored with the sensors. The av. times required for the s.c. implanted sensor to reach its max. current, cor. for sensor response times, were 7.5, 9.8, and 10.0 min for the smallest to the largest dose, resp. The shorter delay in response to the smallest dose was statistically significant. The results were consistent with diln. of the bolus in the cardiovascular system and transport of glucose by both diffusion and facilitated transport via a saturable mediator. An understanding of the differences in the dynamics of venous vs. s.c. response to a glucose dose is important in developing algorithms for the control of blood glucose based on a s.c. measurement. [on SciFinder (R)]