THE METABOLISM OF TRITIATED ESTRADIOL IN THE LAYING HEN

Abstract

The nature of the radioactive metabolites in the tissues of the laying hen soon after the intravenous administration of sub-microgram quantities of [6,7-³H]-estradiol has been examined by solvent partition and paper chromatography. Of the total radioactivity taken up by the tissue, the greatest proportion accountable for as free radio-steroid occurred in the follicle wall (81%), and the greatest proportion accountable for as conjugated radio-steroid was found in the bile (81%). The blood plasma contained approximately equal amounts of free (50%) and conjugated (47%) radio-steroid. The radioactive free steroid fraction of nearly all the tissues studied contained more than one compound, the composition ranging from nearly all estradiol (liver 86%) to virtually no estradiol (follicle wall 5%). In the follicle wall, an unidentified compound constituted a large proportion (83%) of the free radio-steroids; the possible identity of this metabolite is discussed. Labeled estrone was found in significant amounts only in the blood plasma.