Adrenomedullar catecholamine liberation and carbohydrate metabolism during the first 30 min of an aggressive encounter in rats.

The correlation between adrenomedullar catecholamine secretion and metabolic events was investigated in previously isolated fighting male rats. Aggressive encounters were stopped before the apparition of a dominance order. Aggression consisted of short bursts of reciprocal bites, threatening behavior, and short pauses intercalated. After 30 min of fighting, the percent of catecholamine-stained adrenomedullar cells was reduced significantly in fighters. Fighters showed a significant reduction in liver glycogen, while their blood glucose was increased. Muscle-free glucose showed no statistically significant changes compared to controls, while muscle glucose consumption increased. In the muscle of fighting rats, glycogen content was decreased. Our results demonstrated that there is an adrenomedullar activation in early stages of aggression, the changes in carbohydrate metabolism being in correlation with the catecholamine activation.