The isolation of 16-epioestriol from the urine of pregnant women

NADPH-dependent metabolism of estrone by human liver microsomes

We characterized the NADPH-dependent metabolism of estrone (E1) by liver microsomes of 21 male and 12 female human subjects. The structures of 11 hydroxylated or keto metabolites of E1 formed by human liver microsomes were identified by chromatographic and mass spectrometric analyses. 2-Hydroxylation of E1 was the dominant metabolic pathway with all human liver microsomes tested. E1 is more prone to form catechol estrogens (particularly 4-OH-E1) than 17beta-estradiol (E2) and the average ratio of E1 4-hydroxylation to 2-hydroxylation (0.24) was slightly higher than the ratio of E2 4- to 2-hydroxylation (0.20, P < 0.001). An unidentified monohydroxylated E1 metabolite (y-OH-E1) was found to be one of the major metabolites formed by human liver microsomes of both genders. 6beta-OH-E1, 16alpha-OH-E1, and 16beta-OH-E1 were also formed in significant quantities. 16alpha-hydroxylation was not a major pathway for E1 metabolism. The overall profiles for the E1 metabolites formed by male and female human liver microsomes were similar, and their average rates were not significantly different. Hepatic CYP3A4/5 activity in both male and female liver microsomes correlated strongly with the rates of formation of several hydroxyestrogen metabolites. The dominant role of hepatic CYP3A4 and CYP3A5 in the formation of these hydroxyestrogen metabolites was further confirmed by incubations of human CYP3A4 or CYP3A5 with [3H]E1 and NADPH. Notably, human CYP3A5 has very high relative activity for E1 4-hydroxylation, exceeding its activity for E1 2-hydroxylation by approximately 100%. It will be of interest to determine the potential biological functions associated with any of the E1 metabolites identified in our present study.

16-Epiestriol, a novel anti-inflammatory nonglycogenic steroid, does not inhibit IFN-gamma production by murine splenocytes

All the steroidal anti-inflammatory drugs currently available are glucocorticoids. The desired anti-inflammatory activities of glucocorticoids frequently are accompanied by adverse side effects, notably glycogenic activities and profound immunosuppression, that can limit clinical use. We recently identified 16-epiestriol, a naturally occurring steroid, as exhibiting significant anti-inflammatory activity without glycogenic activity. In the present study, we compared the effects of 16-epiestriol and hydrocortisone on the capacity of murine splenocytes to produce interferon-y (IFN-y). We injected young adult male BDF1 mice once with 20 mg/kg hydrocortisone or 20, 5, or 1 mg/kg 16-epiestriol and 4 h later harvested the splenocytes. Flow cytometric analysis confirmed that 16-epiestriol did not alter the number of CD3+ T cells in the spleen. In contrast to the suppressive effects of hydrocortisone, none of the 16-epiestriol concentrations inhibited concanavalin A-stimulated IFN-gamma production by spleen cells, as determined by ELISA. Incubating spleen cells from untreated mice in concentrations of 16-epiestriol ranging from 1 mg/ml to 100 pg/ml did not alter profiles of IFN-gamma production, in contrast to the suppressive dose-response effects of hydrocortisone. Collectively, these results support the contention that 16-epiestriol may be a clinically useful safe anti-inflammatory steroid without profound immunosuppressive activities.

16-epiestriol: an anti-inflammatory steroid without glycogenic activity

All of the steroidal anti-inflammatory drugs currently available are glucocorticoids. They exhibit both glycogenic and anti-inflammatory activities. These two activities are usually considered inseparable. This glycogenic activity is responsible for most of the adverse side effects that severely limit clinical use of currently available steroidal anti-inflammatory drugs. The purpose of this study was to determine if a steroid, 16-epiestriol, could exhibit significant anti-inflammatory activity without glycogenic activity. The anti-inflammatory activity of 16-epiestriol was determined using a modified Winter's carrageenin rat paw edema model. The glycogenic activity of 16-epiestriol was determined by a modification of Venning's methods on liver and plasma glucose concentrations. In each study, 16-epiestriol-treated animals were compared to untreated control and hydrocortisone-treated animals. In the anti-inflammatory study, 16-epiestriol was more than twice as effective as hydrocortisone, on an equimolar basis, in preventing edema. 16-Epiestriol exhibited no effect on the liver or plasma glucose concentration in the glycogenic study. 16-Epiestriol exhibited potent anti-inflammatory activity without glycogenic activity. 16-Epiestriol does not conform to classical steroidal structure-activity relationship theory.

Interconversion of 16-epioestriol and oestriol by avian liver tissue in vitro

1. [16-(14)C]16-Epioestriol and [6,7-(3)H(2)]oestriol were incubated both simultaneously and separately at 40 degrees with hen liver homogenates obtained from birds in the laying stage. 2. Purification and identification of products was made by ether extraction, Girard separation, Celite partition and paper chromatography and crystallization to constant specific activity both with and without derivative formation. Percentage conversions of the radioactive 16-epioestriol and oestriol were calculated from these specific activities. 3. Oestriol yielded 16-epioestriol as early as 5min. after exposure of steroid to the tissue. No production of oestriol from 16-epioestriol was detectable in this time. 4. Considerably more 16-epioestriol was formed from oestriol than oestriol by the reverse reaction after 90min. of incubation. 5. 16-Oxo-oestradiol-17beta appeared in all cases to be the major identified intermediate in the interconversion of 16-epioestriol and oestriol.

Natural Oestrogens and the Safe Level of Oestrogen Intake

Several substances with oestrogenic activity occur in many different species of plants. More assays of oestrogenic activity of food products should be carried out so that the oestrogen intake of different populations can be assessed.

Some women with mammary cancer benefit from the operations of oophorectomy and adrenalectomy. The benefit is probably due to the removal of small amounts of oestrogens that are sufficient for the growth of hormone-dependent tumours. The data indicate that microgram (μg) quantities of oestrogen may facilitate the growth of cancer of the breast. These amounts of oestrogens may therefore present a hazard to post menopausal women.

The administration of oestrogens to cattle, sheep or poultry increases the rate of growth and efficiency of food utilisation. If the hormone is added to food and withdrawn a week before slaughter no oestrogen appears to be present in the meat. The meat and liver of chickens in which oestrogen pellets have been implanted, however, contain amounts of oestrogen that could also facilitate the growth of otherwise dormant hormone dependent tumours.

ISOLATION OF CRYSTALLINE 16-EPIESTRIOL FROM HEN URINE

16-Epiestriol has been isolated in crystalline form from hen urine and characterized on the basis of the melting points of the isolated product and of two of its derivatives (acetonide, triacetate) and on the chromatographic behavior of the isolated product and five of its derivatives in each of three different solvent systems.

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

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.

THE FLUORESCENCE OF EIGHT NATURAL ESTROGENS IN SULPHURIC ACID

The sulphuric acid fluorescence and absorption spectra of eight natural estrogens (estrone, estradiol-17β, estriol, 16-epiestriol, 16-ketoestradiol-17β, 16α-hydroxyestrone, 16-ketoestrone, and 2-methoxyestrone) have been studied with respect to the influence of exciting radiation wavelength, time of heating, acid concentration, and the addition of ethanol or toluene–ethanol. These data are evaluated with respect to optimum fluorescence intensity and specificity.

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

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.