Immunologic Studies of Poisonous Anacardiaceae: Effect of Vehicle on Absorption of 3-n- Pentadecylcatechol and Its Diacetate Ester Derivative after Oral Feeding in Rats

Tritium-labeled 3-n-pentadecylcatechol and its diacetate ester were fed to Sprague-Dawley rats.Both compounds were dissolved in ethanol and in corn oil vehicles and administered by gavage.The rats were placed in metabolic cages,and the urine and feces were collected.The radioactivity excreted in the urine and feces was detemined by liquid scintillation counting,and the percentage of the administered dose was utilized as a measure of absorption.While there was no difference between the absorption of either compound,absorption was affected by the vehicle.Apporximately 30% of the administered radioactivity appeared in the urine when ethnol was the vehicle,but about half that amount (14%) was excreted in the urine when the compounds were dissolved in corn oil.A subsequent bile cannulation study showed that the balabce of the radioactivity found in the feces was not a result of biliary excretion.The majority of the activity recovered from urine and feces was eliminated within 48 hr after dosing.These date indicate that oil is a poor vehicle for GI absorption of urushiol components.