Augmentation of insulin secretion by a non-nutrient drink

Area of Science:

• Endocrinology
• Metabolic Research
• Gastroenterology

Background:

• Nutrients are known to stimulate insulin release.
• The role of non-nutrient stimuli, particularly osmotic load, on insulin secretion requires further investigation.

Purpose of the Study:

• To investigate the effect of a nutrient-devoid hypertonic drink on insulin release.
• To determine if osmotic load influences the insulin secretory response to intravenous glucose.

Main Methods:

• 13 healthy subjects received intravenous glucose infusion.
• The effect of pre-ingesting a 3% mannitol-electrolyte solution (osmolality ≥ 456 mosmol/kg) on insulin response was compared to a control.
• Responses to arginine infusion were also assessed following drink ingestion.

Main Results:

• Ingestion of the hypertonic mannitol-electrolyte drink increased insulin release by 56% during intravenous glucose infusion (P < 0.005).
• Post-infusion serum glucose levels were lower when the drink preceded glucose.
• The drink did not alter basal insulin or other measured hormones, and a less hypertonic solution (2%) lacked this effect. Arginine-stimulated insulin release was not enhanced.

Conclusions:

• A non-nutrient drink with high osmolality augments insulin secretion in response to intravenous glucose.
• Osmotic stimulation appears to be a key factor in enhancing glucose-induced insulin release.
• This finding has implications for understanding nutrient-independent regulation of insulin secretion.