Topic overview

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Glucose homeostasis reflects hepatic glycogen breakdown and gluconeogenesis balanced against uptake by peripheral tissues. Insulin promotes glucose use and storage, while glucagon supports hepatic glucose release; epinephrine, cortisol, and growth hormone also contribute to counter-regulation. The balance changes over time after a meal and during fasting, with gluconeogenesis becoming increasingly important as fasting continues. Tissue-specific GLUT transporters help explain differences in glucose uptake, including insulin-dependent uptake in muscle and adipose tissue. Because the brain and erythrocytes rely on glucose under ordinary conditions, falling levels trigger hormonal responses and may lead to adrenergic or neuroglycopenic manifestations. The lesson also introduces reference ranges, the renal threshold, and diagnostic criteria for diabetes mellitus.