How does a rat die of starvation? - briefly
Food deprivation exhausts a rat’s glycogen, then fat and protein stores, causing severe hypoglycemia, organ failure, and systemic collapse; the resulting loss of essential nutrients inevitably leads to death.
How does a rat die of starvation? - in detail
When food intake ceases, a rat’s body initiates a cascade of metabolic adaptations that ultimately lead to death. The process can be divided into three sequential phases.
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Phase 1 – Glycogen depletion (0–12 hours). Liver glycogen stores are mobilized to maintain blood glucose. Insulin levels fall while glucagon rises, prompting glycogenolysis. As glycogen exhausts, blood glucose drops, causing early signs of hypoglycemia such as lethargy and tremor.
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Phase 2 – Gluconeogenesis and lipolysis (12 hours–3 days). The animal converts amino acids from muscle protein and glycerol from fat into glucose. Fat reserves are hydrolyzed, releasing free fatty acids that are oxidized for energy. Ketone bodies accumulate, providing an alternative fuel for the brain but also contributing to metabolic acidosis. Progressive muscle wasting reduces locomotor ability and impairs respiratory function.
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Phase 3 – Organ failure (3 days onward). Continuous protein catabolism depletes essential structural and functional proteins. Cardiac muscle atrophy compromises circulation; the heart’s output declines, leading to hypotension. The kidneys lose the ability to concentrate urine, resulting in electrolyte imbalance and dehydration. Hepatic cells suffer from fatty infiltration and necrosis, impairing detoxification and coagulation. The immune system collapses, making the animal vulnerable to opportunistic infections. Ultimately, severe hypoglycemia, electrolyte disturbances, and cardiac arrhythmia culminate in circulatory collapse and death.
Throughout the progression, physiological markers include falling blood glucose, rising blood urea nitrogen, elevated serum ketones, and decreasing body temperature. The combination of energy shortage, organ degeneration, and systemic acidosis defines the lethal outcome of prolonged food deprivation in rodents.