Hepatic glucose extraction in normal and diabetic man

Area of Science:

• Metabolism
• Endocrinology
• Physiology

Background:

• Hepatic glucose uptake is crucial for glucose homeostasis.
• Understanding fractional hepatic extraction is key to metabolic research.
• Non-insulin-dependent diabetes mellitus (NIDDM) involves altered glucose metabolism.

Purpose of the Study:

• To quantify fractional hepatic glucose extraction under various glycemic and insulinemic conditions.
• To investigate the impact of hyperinsulinemia and hyperglycemia on hepatic glucose uptake.
• To determine hepatic glucose extraction in normal subjects and patients with NIDDM.

Main Methods:

• Utilized the glucose clamp technique to maintain steady-state glycemia and insulinemia.
• Administered oral 3-[3H]glucose to label portal vein glucose.
• Measured systemic appearance of labeled glucose to determine fractional extraction.

Main Results:

• Fractional hepatic glucose extraction was 19% in normal subjects under basal conditions.
• Extraction increased to 32% with hyperinsulinemia (with or without hyperglycemia).
• Hepatic glucose uptake accounted for 50-72% of total glucose utilization in various states.

Conclusions:

• Hepatic glucose extraction is an active process even in basal physiological states.
• Hyperinsulinemia significantly enhances hepatic glucose extraction.
• Fractional hepatic glucose extraction is not altered in non-insulin-dependent diabetes mellitus.