FORMATION IN VIVO OF 16-EPIESTRIOL AND 16-KETO- ESTRADIOL-17β FROM ESTRIOL BY THE LAYING HEN AND OCCURRENCE OF EQUOL IN HEN'S URINE AND FECES

Abstract

Estriol-16-C14was administered intravenously to a laying hen furnished with exteriorized ureters. Urine and feces were collected separately and estrogens were extracted by a method that included acid hydrolysis but avoided a highly alkaline pH (> 10.5) for the extract. The urine secreted in the first 24-hour period after injection contained radioactive estriol, radioactive 16-ketoestradiol-17β, and radioactive 16-epiestriol. No other radioactive metabolite was detected in the urine. The feces excreted in the first 24-hour period after injection contained radioactive estriol and radioactive 16-epiestriol, but little, if any, radioactive 16-ketoestradiol-17β. The feces did contain small amounts of a radioactive metabolite less polar than estradiol-17β. Reasons are advanced in support of the view that this metabolite was present in consequence of bacterial action in gut or feces. Comparison of blackening of radioautograms showed that a high proportion of the injected estriol was excreted by the fecal route, and that the greatest single fraction of radioactivity present was in 16-epiestriol. The urine and feces for the second 24-hour period contained insignificant amounts of radioactive estrogens as compared with those excreted in the first 24-hour period.The lipophilic and hydrophilic fractions of estrogen extracts both from urine and feces contained amounts of equol that were large relative to the amounts of the various estrogens excreted, as judged by staining of the chromatograms. Extracts from the first and from the second 24-hour periods contained about the same amount of equol.