Insulin oscillations per se do not affect glucose turnover parameters in normal man

Area of Science:

• Metabolic studies
• Endocrinology
• Glucose metabolism

Background:

• Insulin delivery methods, continuous vs. pulsatile, have different physiological profiles.
• Understanding their metabolic impact is crucial for diabetes management.

Purpose of the Study:

• To compare the metabolic effects of continuous versus pulsatile intravenous insulin infusion.
• To assess glucose turnover and hormonal responses in normal men.

Main Methods:

• Normal men received glucose-controlled intravenous glucose infusions with inhibited endogenous hormone secretion and replaced glucagon.
• Insulin was administered either continuously or pulsatilely over 260 minutes.
• Glucose turnover was measured using [3H]glucose infusion, with continuous monitoring of blood glucose and glucose infusion rates (GIR).

Main Results:

• Both infusion methods led to suppressed C-peptide and elevated glucagon levels.
• Plasma insulin levels differed, but glucose appearance rate and endogenous glucose production (EGP) initially increased in both tests.
• Over time, EGP declined, and glucose uptake increased, with no significant differences in GIR or other parameters between continuous and pulsatile insulin delivery.

Conclusions:

• Continuous and pulsatile intravenous insulin infusions demonstrate equivalent metabolic effects on glucose turnover in healthy individuals.
• Both methods effectively inhibit glucagon-stimulated EGP and promote peripheral glucose uptake.
• Physiological peripheral plasma insulin levels achieved by either method similarly impact glucose metabolism.