Identification of conjugated estrogen metabolites in dog plasma following administration of estriol-2,4,6,7-3H

Testosterone metabolites in dog bile

Testosterone-1,2-3H was injected intravenously into a male dog with a bile fistula and bile and urine collected. The radioactivity was excreted preponderantly in bile (52% of the injected dose) in 6 hours; only 12% appeared in the urine. Methods to study the biliary metabolites of testosterone in this and other animals were developed. Satisfactory conjugate patterns were obtained by fractionation on DEAE-Sephadex A-25 columns using two different elution systems. In addition to an unchanged fraction, six different monoglucuronide fractions were separated. No other conjugates were isolated. Lipidex 5000 column chromatography, TLC and paper chromatography were used for the isolation and purification of aglycone metabolites, which were further identified by co-crystallization methods. The biliary metabolites of testosterone were epiandrosterone (3beta-hydroxy-5alpha-androstan-17-one), etiocholanlone (3alpha-hydroxy-5beta-androstan-17-one), 5alpha-androstan-3beta, 17beta-diol, 5beta-androstan-3alpha, 17beta-diol and 5beta-androstan-3beta,17beta-diol.

Estrogen metabolism in nonhuman primates. I. In vitro biosynthesis of estrogen glucosiduronates in rhesus monkey liver

Estrone glucosiduronate, 17beta-estradiol-3-glucosiduronate, 17beta-estradiol-17-glucosiduronate and estriol-16alpha-glucosiduronate have been biosynthesized in substantial yield by incubation of radioactive estrone, 17beta-estradiol, estriol and uridine diphosphoglucosiduronic acid with rhesus monkey liver homogenates. The metabolites were characterized by chromatography on Celite and DEAE-Sephadex, enzyme hydrolysis, derivative formation and crystallization to constant specific activity. The percent conversion to 17beta-estradiol-17-glucosiduronate from 17beta-estradiol ranged between 56-71%; from estrone, the conversion was 49-54%. Other metabolites formed from estradiol were estrone glucosiduronate (12-21%) and 17beta-estradiol-3-glucosiduronate(5-12%). The same metabolites derived from estrone accounted for 18-28% and 10-14% respectively. After estriol incubation, more than 90% of the steroid was converted to estriol-16alpha-glucosiduronate with no detectable estriol-3-glucosiduronate. This report represents the first time that 17beta-estradiol-17-glucosiduronate has been reported as a metabolite in the rhesus monkey and this is the only known species which forms 17beta-estradiol-17-glucosiduronate as the predominant metabolite of either estrone or estradiol in vitro. Rhesus monkey liver is similar to the human and baboon in that it metabolizes estriol exclusively to estriol-16-glucosiduronate.

Splanchnic and intestinal uptake and formation of estriol and estriol conjugates in the dog in vivo

A loading dose of 3H-estriol was given to male dogs followed by a constant infusion. The concentrations of total radioactivity, conjugated estriol metabolites, estriol, estriol-o-glucosiduronate, estriol-16alpha-glucosiduronate, estriol-3-sulfate and estriol-3-sulfate, 16alpha-glucosiduronate were determined in plasma from the femoral artery(A), hepatic vein(HV) and superior mesenteric vein (SMV). From these values the splanchnic (100[1-HV/A]) and intestinal (100[1-SMV/A]) extractions were calculated. The mean splanchnic extraction of total radioactivity was positive (23, SE 3, P less than .01), indicating net uptake by the splanchnic area, possibly due to biliary excretion. The mean splanchnic extraction of estriol was 77, SE 1, P less than .01, also indicating net uptake. The splachnic extractions of estriol-3-glucosiduronate, estriol-16alpha-glucosiduronate and estriol-3-sulfate were negative (-15, SE 3, P less than .01; -23, SE 6, P less than .01; -31, SE 8, P less than .01 respectively) indicating net formation of these conjugates for release into the systemic circulation. The mean intestinal extraction of estriol was 12, SE 4, P less than .01, indicating net uptake by the intestine. This net uptake was associated with mean negative intestinal extractions of estriol-3-glucosiduronate (-15, SE 7, P approximately .05), estriol-3-sulfate (-33, SE 10, P less than .01) and estriol-3-sulfate, 16alpha-glucosiduronate (-53, SE 13, P less than .01), indicating net formation of these conjugates by the intestine.