Melatonin's role in controlling blood sugar in the freshwater edible crab

Melatonin injection induced hyperglycemia in the freshwater edible crab, Oziotelphusa senex senex, in a dose-dependent manner.

• Both intact and eyestalk-ablated crabs exhibited hyperglycemia after melatonin administration.
• Bilateral eyestalk ablation significantly increased total carbohydrates and glycogen levels.
• Phosphorylase activity decreased in the hepatopancreas and muscle of crabs following eyestalk ablation.
• Melatonin injection led to a significant decrease in total carbohydrate and glycogen levels.
• Increased phosphorylase activity in the hepatopancreas and muscle was observed after melatonin injection in both crab types.
• Melatonin-induced hyperglycemia appears not to be mediated by eyestalk hyperglycemic hormone.

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