Effect of time on measurement of hepatic glucose production.

Basal hepatic glucose production (HGP) was determined in obese and nonobese normal subjects and patients with noninsulin-dependent diabetes mellitus (NIDDM) using [3-3H]glucose and the nonsteady state equations of Steele. When HGP was estimated at hourly intervals from 0800-1300 h, it became evident that calculated values for HGP fell for the first 2-4 h until a plateau was reached, and this decline was quite precipitous during the first 2 h in patients with NIDDM. Furthermore, when the same patient with NIDDM was studied on two occasions, similar values for HGP were not uniformly obtained unless measurements were made at least 4 h after [3-3H] glucose administration. Since it has been the convention to use the nonsteady state equations of Steele to calculate HGP in patients with NIDDM 2 h after [3-3H] glucose administration, it is almost certain that published values for HGP in patients with NIDDM are falsely high. Based upon the data presented, we suggest that HGP using [3-3H]glucose and the nonsteady state Steele equations be measured for at least a 4-h period in patients with NIDDM in order to increase the validity of the calculated value.