Impact of Plasma Lipids on β Cell Function and Insulin Sensitivity

Impact of Plasma Lipids on β Cell Function and Insulin Sensitivity

The investigators aim to evaluate whether and to what extent glucose tolerance, beta cell function, insulin clearance, and glucose metabolic fluxes change in response to an acute increase in plasma triglycerides during lipid infusion, independently of free fatty acid (FFA) levels, in nondiabetic subjects.

Mild hypertriglyceridemia is associated with reduced glucose tolerance and increased risk of type 2 diabetes, independent of obesity, in both cross-sectional and prospective studies. It is unclear whether this association is direct or mediated by circulating lipid substrates of triglycerides (free fatty acids, or FFA) and which are the mechanisms involved.

To comprehensively examine the effects of mild acute hypertriglyceridemia on major glucose homeostatic mechanisms involved in diabetes progression, two dual-labeled oral glucose tolerance tests (OGTT) during 5-hour intravenous infusions of either 20% Intralipid or normal saline will be performed in healthy lean volunteers. Lipid-induced changes in glucose tolerance and insulin metabolism will be evaluated.

Inclusion Criteria:

• age 18-65 years
• Body mass index (BMI) 18-35 kg/m2
• both women and men

Exclusion Criteria:

• chronic or acute diseases
• any medications
• pregnancy