Biodistribution and excretion of [¹¹C]benzaldehyde by the rat after two-minute inhalation exposures

Abstract

1. Based on the decay characteristics of short-lived gamma-emitting radioisotopes a new acute exposure method was developed for studying the kinetics and biodistribution of inhaled toxic agents. Such body-penetrating radiation allows direct, non-invasive determination of the radiation in the animal at any time.

2. Rats exposed to ¹¹C-labelled benzaldehyde for 2min accumulated an average of 2.5μg of this aldehyde.

3. Inhaled benzaldehyde was rapidly absorbed and at 1.5 min after exposure only 0.8% of the administered dose was resident in the lungs. This aldehyde was quickly distributed with the peak radioactivity in the organs occurring at 1.5 min after exposure. Subsequent loss of radiolabel from tissues was rapid and paralleled the removal from the blood. The adipose tissue cleared most slowly.

4. Benzaldehyde was rapidly excreted via the renal system with the kidneys containing 17% of the total administered activity at 5 min. The excreted radiolabeled compound cochromatographed with hippuric acid on t.l.c.