Studies on the Metabolism of<i>d</i>-Limonene (<i>p</i>-Mentha-1,8-diene): I. The Absorption, Distribution and Excretion of<i>d</i>-Limonene in Rats

Abstract

1. The absorption, distribution and excretion of d-limonene were investigated in rats using the 14C-labelled compound.2. The highest concentration of radioactivity in blood was obtained 2 h after oral administration of [14C]d-limonene and most occurred in the serum fraction. Radioactivity in the tissues reached maximum 1 or 2 h after administration. Radioactivity in liver, kidney and blood was higher than in other tissues, but was negligible 48 h after administration. An autoradiographic study confirmed these findings of tissue distribution.3. About 60% of administered radioactivity was recovered from urine, 5% from faeces and 2% from expired CO2 within 48 h. In bile duct cannulated rats, about 25% of the dose was excreted in bile within 24 h.