The modified insulin suppression test to measure insulin resistance is described as follows

Patients initially receive 25 μg of octreotide (Sandostatin) in 5 mL of normal saline over 3 to 5 minutes via intravenous infusion (IV) as an initial bolus, and then, are infused continuously with an intravenous infusion of somatostatin (0.27 μg/m2/min) to suppress endogenous insulin and glucose secretion. Next, insulin and 20% glucose are infused at rates of 32 and 267 mg/m2/min, respectively. Blood glucose is checked at zero, 30, 60, 90, and 120 minutes, and thereafter, every 10 minutes for the last half-hour of the test. These last four values are averaged to determine the steady-state plasma glucose level (SSPG). Subjects with an SSPG greater than 150 mg/dL are considered to be insulin-resistant.

The description refers to achieving a plasma glucose steady state. But for the given insulin infusion rate + some fixed level of insulin resistance by the cells disposing/clearing glucose from plasma (i.e. muscle,etc.), there will be a certain constant glucose disposal rate D. If that rate is less than the glucose infusion rate I, then shouldn't the plasma glucose level just continuously increase and never achieve a steady state?

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    Welcome to the site. Please take a tour and read the help center pages. One of the conditions for questions on this site is that they make some effort to provide evidence that they have looked for an answer themselves. I'm sure that someone will have done the calcs - you might be able to find out, even through the link you provided... (hint: 45).
    – bob1
    Commented Jul 25, 2022 at 2:29
  • I did attempt to find the answer myself, but I'm still not clear what it is. I looked in the source cited by Wikipedia (journals.physiology.org/doi/full/10.1152/…) and it only says "... The constant infusions of insulin and glucose will determine steady-state plasma insulin (SSPI) and glucose (SSPG) concentrations. The steady-state period is assumed to be from 150 to 180 min after initiation of the IST. SSPI concentrations are generally similar among subjects. "
    – cdog1350
    Commented Jul 25, 2022 at 14:50
  • That does not answer my question above on how a steady glucose state (SSPG) can even be achieved in principle here, since with insulin resistance the glucose clearance rate (assuming a fixed insulin infusion rate) will be lower than the glucose infusion rate, and so a steady state of glucose in plasma will never be achieved.
    – cdog1350
    Commented Jul 25, 2022 at 14:53
  • The assumption is that the clearance rate is never above the infusion rate. Fig 1 in that paper gives some graphs of this (admittedly not clear), and they reference this one for the data.
    – bob1
    Commented Jul 25, 2022 at 19:53
  • That reference is for the glucose clamp technique, not the modified insulin suppression test. Also, if the assumption is that the clearance rate C is never above the infusion rate I, that in itself implies glucose will never reach a stable state (but continue to climb), unless C=I precisely.
    – cdog1350
    Commented Jul 25, 2022 at 20:13


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