Measurements of Insulin-Mediated Glucose Disposal Are Stable Over Time1

To evaluate the stability of insulin-mediated glucose disposal, over time, we measured the steady-state plasma insulin (SSPI) and steady-state plasma glucose (SSPG) concentrations in response to a continuous infusion of SRIF (5 microg/min), insulin (25 microU/m2 x min), and dextrose (240 microg/m2 x min). These measurements were made in 15 healthy volunteers, studied before and after a mean (+/-SEM) interval of 48 +/- 2 months. The mean (+/-SEM) weight of the volunteers did not increase with time (75.4 +/- 3.1 vs. 76.6 +/- 3.2 kg), and there was no significant variation between the 2 mean (+/-SEM) values of either SSPI (324 +/- 18 vs. 372 +/- 24 pmol/L) or SSPG (8.4 +/- 1.0 vs. 8.2 +/- 1.0 mmol/L). Given the similarity of both SSPI and SSPG concentrations at baseline and follow-up, it can be concluded that insulin-mediated glucose disposal was stable in these 15 individuals over an interval of approximately 4 yr.