Studies on the Metabolism ofd-Limonene (p-Mentha-1,8-diene): I. The Absorption, Distribution and Excretion ofd-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.