Abstract
Aims: To evaluate the effects of brain insulin on endogenous glucose production in fasting humans, with a focus on hepatic glucose release by performing a randomized, placebo-controlled, blinded, crossover experiment. Materials and methods: On two separate days, 2 H 2 -glucose was infused to nine healthy lean men, and blood was sampled from the hepatic vein and a radial artery. On day 1, participants received 160 U human insulin through nasal spray, and on day 2 they received placebo spray, together with an intravenous insulin bolus to mimic spillover of nasal insulin to the circulation. Hepatic glucose fluxes and endogenous glucose production were calculated. Results: Plasma insulin concentrations were similar on the two study days, and no differences in whole-body endogenous glucose production or hepato-splanchnic glucose turnover were detected. Conclusions: Nasal administration of insulin does not influence whole-body or hepatic glucose production in fasting humans. By contrast, pharmacological delivery of insulin to the brain might modulate insulin effectiveness in glucose-producing tissue when circulating insulin levels are elevated; therefore, the metabolic consequences of brain insulin action appear to be dependent on metabolic prandial status.
Original language | English |
---|---|
Journal | Diabetes, Obesity and Metabolism |
Volume | 21 |
Issue number | 4 |
Pages (from-to) | 993-1000 |
ISSN | 1462-8902 |
DOIs | |
Publication status | Published - 2019 |
Keywords
- basal insulin
- clinical physiology
- liver