Figure 2. Insulin kinetics after glucose ingestion.

Rate of total insulin delivered to the liver, comprising the rate of insulin secreted from β cells (white bars) and the rate of insulin recycled from the systemic circulation back to the liver (gray bars) (A), fractional hepatic insulin extraction (B), rate of total hepatic insulin extraction (C), rate of total extrahepatic insulin extraction (D), absolute contribution of hepatic (white bars) and extrahepatic (gray bars) insulin extraction to the total rate of whole-body insulin extraction (E), and relative contribution of hepatic (white bars) and extrahepatic (gray bars) extraction to the total rate of whole-body insulin extraction (F) in the lean-NL (n = 14), obese-NL (n = 23), and obese-NAFLD (n = 21) groups. Values represent the mean ± SEM and indicate the averages for 3 hours after glucose ingestion. A 1-way ANCOVA with race and sex as covariates and post hoc testing where appropriate were used to identify significant mean differences between groups. *P < 0.05, value significantly different from the lean-NL value; ^† P < 0.05, value significantly different from the obese-NL value. Relationship between insulin delivery to the liver and the rate of total hepatic insulin extraction (G) and relationship between the insulin delivery rate into the systemic circulation and the rate of total extrahepatic insulin extraction (H) in lean-NL (white circles; n = 14), obese-NL (gray circles; n = 23), and obese-NAFLD (black circles; n = 21) participants. Logarithmic and linear regression analyses were performed to determine the line of best fit to the data in G and H, respectively.