Adrenaline-stimulated, aspirin-sensitive synthesis of histamine in the rat.

The intravenous injection of 10 microgram/kg of adrenaline raised total rat lung histamine from 5.3 +/- 0.7 microgram to 8.4 +/- 0.7 microgram and rat skin histamine from 624 +/- 51 microgram to 835 +/- 85 withing 5 min. These changes were no longer apparent after 10 min. Stomach histamine was raised by a statistically non-significant extent, intestinal histamine was unaffected. Blood drawn 2 min after the injection of adrenaline failed to show an increased content of histamine. Rats given 1 mg/kg of compound 48/80, had greatly elevated levels of histamine in blood, but exhibited no increase in lung histamine. This result, as well as the extent of the increase of histamine observed in skin, which cannot be accounted for in any other way, point towards stepped-up local synthesis as the origin of the effect of adrenaline. Aspirin (20 mg/kg, intravenously, 10 min prior to adrenaline), prevented increases of skin histamine. Evidence suggesting mast cells as the site of action of adrenaline, is discussed.