The excretion of microgram doses of hexoestrol by rabbits and rats

Abstract

Hexoestrol generally labeled in stable positions with tritium was injected subcutaneously in arachis oil solution at microgram dose levels into 2 rabbits and 10 rats. One rabbit received 100[upsilon]g; the other rabbit and the rats each received 1[upsilon]g. The outstanding feature of the metabolism of the estrogen is rapid excretion, either unchanged or as an unidentified non-volatile metabolite. Up to 90% of the initial dose was recovered in urine and feces. Excretion by both routes was substantial although the amount of radioactive material in the feces was up to 4 times as much as in the urine. In some experiments, however, more was excreted in the urine than in the feces. Total oxidation as revealed by the specific activity of the body water was negligible and certainly less than 2% of the initial dose. The amounts of labeled material circulating attached to the blood solids and remaining un-absorbed at the site of injection after 8 hours or more was also negligible. The results are broadly in agreement with earlier work carried out on the same and other synthetic estrogens with very much larger doses.