Transcellular Barriers to Glucose Delivery in the Body.

Area of Science:

• Cellular Biology
• Metabolism
• Physiology

Background:

• Glucose is the primary energy source for mammalian cells, necessitating efficient transport across various biological barriers.
• Maintaining glucose homeostasis requires matching supply with demand, which involves overcoming cellular barriers in the intestine, kidney, and brain endothelium.
• The liver plays a key role in glucose storage and production, requiring intact release into circulation.

Purpose of the Study:

• To provide an updated overview of glucose handling by key organs including the gut, liver, brain endothelium, and kidney.
• To discuss the molecular mechanisms underlying glucose translocation across cellular barriers.
• To address open questions and diseases related to glucose delivery and homeostasis.

Main Methods:

• Literature review of current knowledge on glucose transport mechanisms.
• Analysis of molecular pathways involved in glucose sparing and translocation.
• Discussion of physiological and pathological conditions affecting glucose homeostasis.

Main Results:

• Glucose faces significant barriers in absorption, reabsorption, and transit across endothelia, especially in the brain.
• Mechanisms exist to prevent glucose degradation during transit, ensuring delivery to tissues.
• A common pathway involving endoplasmic reticulum transfer is proposed for glucose translocation across epithelial and endothelial cells.

Conclusions:

• Glucose translocation across cellular barriers is a critical process for systemic energy balance.
• Common molecular mechanisms, potentially involving the endoplasmic reticulum, facilitate glucose transport and prevent its catabolism.
• Further research is needed to fully elucidate these mechanisms and their implications in disease.