A relatively normal plasma glucose rate of clearance for a 7

A relatively normal plasma glucose rate of clearance for a 70 kg adult is about 2.13 mg/kg/min. If the plasma glucose is maintained at 5 mM, how long (in hours) would it take before glycogen stores would be utilized. Lastly, calculate the net glucose export from the liver (in grams/hr) required to maintain a plasma glucose of 5 mM with a clearance rate of 2.13 mg/kg/min.

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Solution

SOLUTION:

Clearance rate of glucose = 2.13mg/Kg/min

Glucose consumed per minute by a 70kg man = 2.13 X 70 = 149.1mg/min = 0.1491g/min

Amount of plasma glucose (in grams) = No. of moles X Molar mas = 5X10^-3 X 180 =0.90 g

0.90g will last for = 0.9 / 0.1491 = 6.03 min = 6.03 / 60 = 0.1005hr, hence after 0.1005 hr glycogen stors will be utilised.

The 70kg man needs 149.1 mg of glucose per minute

No. of moles of glucose need per minute = 0.1491/180 = 0.00083M = 0.83mM

Hence the export from liver must be 0.83mM per minute to maintain 5mM plasma glucose.

Export rate per hour = 0.83mM X 60 = 49.8mM/hr