The influence of phentolamine on the hyperglycaemic and lipolytic effects of ammonia in sheep.

Intravenous infusion over 30 min of ammonium chloride [10-1 g/kg b.w.] caused a significant increase of blood glucose and free fatty acids levels, and a similar effect was observed with adrenaline. Phentolamine [1 mg/kg b.w.] abolished the hyperglycaemic action of ammonium chloride but only slightly diminished the lipolytic effect. It is concluded that the ammonium ion influences carbohydrate metabolism chiefly by way of catecholamines and stimulation of alpha-adrenergic receptors, while tissue lipids are mobilized by ammonia by another route, possibley directly.