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At least 19 recordsLinked to original sources
PubMed1978

16-Hydroxylation of estrone-3-sulfate and estrone in the guinea pig in vivo.

[6,7-3H]Estrone-3-sulfate or [6,7-3H]-estrone of high specific activity was injected into adult female English Shorthair guinea pigs. Blood, liver, kidney, gall bladder bile, and urine were obtained and investigated for metabolites. Chromatographic procedures followed by enzymatic or solvolytic cleavage of conjugates and subsequent crystallization with appropriate carrier steroids revealed the pattern of metabolites formed. Injected estrone sulfate was partially hydrolyzed and reconjugated, resulting in the production of estrone and estradiol glucuronides. The main metabolites, however, were monosulfates of 16alpha-hydroxyestrone, 16-keto-17beta-estradiol, and estriol as well as disulfates of 16alpha-hydroxyestrone, estriol, and 16beta-hydroxyestrone. Particularly high amounts of these were found in urine. By far the main metabolites of injected estrone were glucuronides of estrone and estradiol, although the pattern of mono- and disulfated steroids was qualitatively similar to that found after estrone sulfate injection. It is concluded that the guinea pigs employed in the study hydroxylated estrogen in the 16alpha- and 16beta-configurations and that this activity was much more pronounced after injection of estrone sulfate than after estrone.

Animals↗
PubMed1979

A comparison of the in vitro metabolism of estrone, estradiol-17 beta and estrone-3-sulfate by the livers of young virgin female, pregnant and female fetal guinea-pigs.

The metabolism, in vitro, of [3H]-estrone, [3H]-estradiol-17 beta and [13H]-estrone-3-sulfate by the livers of pregnant, young virgin female and female fetus guinea-pigs has been compared using 900 g supernatants and microsomes. The ability of the guinea-pig livers to synthesize polyhydroxylated estrogens has been fo-nd to be small. The major metabolites isolated were unconjugated estrone and estradiol-17 beta or their glucuronides. The percentage of sulfates was lower after incubations with [3H]-estrone than with [3H]-estradiol-17 beta. A kinetic study with microsomes has shown a direct conversin of estrone-sulfate to estradiol sulfate. Fetal microsomes have been found to exhibit a more active hydrogenation of estrone to estradiol-17 beta than microsomes from young female or pregnant animals.

Animals↗
PubMed1978

[In vitro comparative metabolism of 6,7-3H estrone and 6,7-3H estrone-3-sulfate in maternal and fetal guinea-pig liver].

The metabolism of [6,7-3H] estrone and of [6,7(3)H] estrone-3-sulfate have been comparatively studied in the maternal and fetal guinea-pig livers. The appearance of estradiol-17 beta resulting from the activity of the 17 beta-hydroxysteroid-dehydrogenase is more important in the fetal than in the maternal hepatic tissue. This suggests the direct transformation of estrone-3-sulfate into estradio-3-sulfate in the fetus. After incubation of the [3H] estrone, there is an abundant hepatic conjugation. The glycuroconjugated components are predominant, as well in the maternal as in the fetal hepatic tissue. For the latter-one the sulfoconjugation is inexistant. The sulfatasic activity shown after the incubation of [3H] estrone-3-sulfate is very low in the fetal hepatic tissue; in contrast, this activity is higher in the maternal tissue.

Animals↗
PubMed1975

Production of estrone and fractional conversion of circulating androstenedione to estrone in women with endometrial carcinoma.

Postmenopausal women convert circulatory C19 steroids to estrogen. In order to study the possible role of such estrogen in endometrial cancer, the determination of the fractional conversion of circulation delta-4-androstene-3,17-dione to estrone was attempted. However, in the course of this work it became apparent that the mathematical model upon which this determination is based does not adequately represent the true physiological conditions. The reasons for the inadequacy of the model are not apparent, although they seem to bear some relationship to obesity. The direction and magnitude of the deviation of the values; determined from the true values are unknown. The values for the apparent fractional conversion of androstenedione to estrone in 9 postmenopausal women with endometrial cancer are strongly correlated with values indices of obesity. These values also correlate well with values for the apparent rate of production of estrone in our 9 patients and also in 5 postomenopausal patients with uterine bleeding reported in the literature, but no such correlation is evident for postmenopausal women without endometrial abnormality reported in the literature. The range of values for both the apparent fractional conversion and the apparent rate of production of estrone are similar to those reported by other workers using the same model. However, the data suggest that women with endometrial cancer may produce estriol by a pathway not involving circulating estrone.

Adenocarcinoma↗
PubMed1979

Antisera reactive directly to estrone sulfate.

Derivatives of estrone were prepared and linked to bovine serum albumin or its methyl-esterified form to produce immunogens which were effective in raising antisera to estrone sulfate. The most effective was estrone-3-methylphosphonothioate, electrostatically complexed with methylated bovine serum albumin. The ionically combined hapten functioned as an antigenic determinant as do covalently bound haptens when administered to sheep in emulsions with Freund's complete adjuvant. Estrone-3-phosphate covalently or electrostatically linked to bovine serum albumin also produced antisera reactive to estrone sulfate. Estrone sulfate itself, after electrostatically complexing to methylated bovine serum albumin and administration with Freund's complete adjuvant to sheep, was ineffective in producing antisera. The sera which had workable titres to estrone sulfate showed considerable cross-reaction with free estrone but was otherwise highly specific with little or no reaction with other steroid sulfates, glucosiduronates or other free steroids. Radioimmunoassay curves using [6,7-3H]-estrone sulfate were highly sensitive and were effective in the range of 5-250 pg estrone sulfate.

Cross Reactions↗
PubMed1975

Dynamics of estrone glucosiduronate metabolism in dogs.

Interest in the metabolism of estrogen conjugates has been increased by the recent demonstration that some of these conjugates can be hydrolysed in vivo, and are thus a source of physiologically-active circulating estrogens. In this report the metabolism of the quantitatively important conjugate estrone glucosiduronate has been studied in dogs, following the intravenous infusion of 3H-estrone glucosiduronate. Arterial plasma levels of radioactive estrone glucosiduronate and of the radioactive metabolites estrone, estradiol-17beta-3-glucosiduronate and estradiol-17alpha-3-glucosiduronate were measured. The metabolic clearance rate of estrone glucosiduronate (MCREG) was determined, as well as conversion ratios for estrone glucosiduronate to estrone (CREG.E), estradiol-17beta-3-glucosiduronate (CREG.E2betaG) and estradiol-17alpha-3-glucosiduronate (CREG.E2alphaG). Sequential values for the above mentioned conversion ratios were obtained and the relationship to time was analysed. Transfer constants for estrone glucosiduronate to estrone (rhoEG.E) were measured. The mean MCREG was 329 L/day/m2, SE 35. The values for CREG.E2betaG and CREG.E2alphaG did not become constant until 80 minutes following the start of infusion. The mean values at a steady state were: CREG.E.021, SE .002, CREG.E2betaG .068, SE .005, CREG.E2alphaG .022, SE .002. The mean value for rhoEG.E was .057, SE .006.

Animals↗
PubMed1975

Relationships between immunoreactive estrone and estradiol in milk, blood, and urine of dairy cows.

Quantities of immunoreactive estrone and estradiol in blood plasma, urine, and milk were measured during the estrous cycle and pregnancy of cows. The objectives were to develop a radioimmunoassay procedure for quantifying estrogen in milk and urine and to compare changes in milk estrogen with those in blood plasma and urine. Concentrations of estrone and estradiol in milk varied during the estrous cycle. Relative concentrations of estradiol in blood plasma and milk were not different, but average estrone concentrations in milk were four times greater than those in blood plasma. Concentration of total estrogen (estradiol plus estrone) exceeded 1 ng/ml in colostrum and milk from cows milked prepartum, and was correlated with total estrogen in blood plasma and urine before and after calving. Blood plasma estrone was correlated only with milk estrone whereas blood plasma estradiol was correlated with urinary estradiol, milk estrone, and milk estradiol during the estrous cycle. These results raise possibilities that mammary gland of the lactating cow may concentrate preferentially estrone or convert estradiol to estrone. However, estimated excretion of estrogen through the milk represents no more than a fraction of 1% of the total excreted during the estrous cycle, and the proportion becomes less as gestation progresses up to at least 7 mo.

Animals↗
PubMed1976

Investigations on the kinetic properties of estrone glucuronyltransferase from pig kidney.

The microsomal fraction of the pig kidney catalyzes the glucuronidation of estrone in the presence of UDP-glucuronic acid. This bireactant system exhibits a sequential type of reaction mechanism. Increasing concentrations of either substrate increase the affinity of the enzyme for the other substrate. The Hill coefficient, n, was calculated to be 1.0 for both estrone and UDP-glucuronic acid. The Kestrone and KUDP-glucuronic acid are 6.6 muM and 254 muM, respectively. The estrone glucuronyltransferase (UDP-glucuronate: 17 beta-oestradiol 3-glucuronosyltransferase, EC 2.4.1.59) exhibits high substrate specificity in that it is inhibited noncompetetively by estradiol-17 beta, estradiol-17 alpha, estriol, testosterone, phenolphthalein and bilirubin; p-nitrophenol and o-aminophenol do not inhibit the glucuronidation of estrone. Mg2+ and Ca2+ were found to be nonessential activators. One of the two products of the reaction, estrone glucuronide, inhibits the enzyme competitively in the presence of increasing concentrations of UDP-glucuronic acid. The other product of the reaction, UDP, inhibits the enzyme noncompetitively with varying estrone concentrations and uncompetitively with varying UDP-glucuronic acid concentrations. Under incubation conditions for the glucuronidation of estrone, the enzyme catalyzes the reverse reaction with estrone glucuronide and UDP as reactants to an extent of about 0.4% of the forward reaction; this reverse reaction is also of a sequential type.

Adenosine Triphosphate↗
PubMed1978

A specific radioimmunoassay for estrone sulfate in plasma and urine without hydrolysis.

Estrone sulfate, quantitatively the most important estrogen in plasma, has previously been determined only after hydrolysis and chromatography. An antiserum raised against estrone glucosiduronate-bovine thyroglobulin was found to be suitable for the specific RIA of estrone sulfate both in plasma and urine. Plasma levels were measured after solvent extraction without hydrolysis or chromatography. The mean (+/-SE) was 972 +/- 79 pg/ml (range, 537-1581) in 15 women in the follicular phase, 1806 +/- 160 pg/ml (range, 814-3358) in 15 women in the luteal phase, and 922 +/- 62 pg/ml (range, 461-1238) in 13 men. The urinary excretion of estrone sulfate, measured after simple chromatographic separation, ranged from 0.8-7.9 micrograms/24 h in men and 5.1-18.7 micrograms/24h in nonpregnant women. This was generally one-seventh to one-half the simultaneous estrone glucosiduronate excretion rate. An approximate mean renal clearance of estrone sulfate calculated from the above values was 2.7 ml/min. The low clearance rate is taken to reflect extensive binding of estrone sulfate by plasma proteins. The splanchnic extraction of estrone sulfate measured in 6 patients undergoing hepatic vein catheterization for diagnostic purposes was 29.8 +/- 11.1%, indicating net uptake of this compound by the splanchnic area.

Antibody Specificity↗
PubMed1977

Membrane-bound estrone as substrate for microsomal UDP-glucuronyltransferase.

Nonpolar substrates of microsomal UDP-glucuronyl-transferase partition between the hydrophobic phase of the microsomal membrane and the bulk aqueous phase in a suspension of microsomes in water. Partitioning of estrone into the membranes was measured in the studies presented and was extensive. Comparison of the rate of conjugation of estrone and the rate of its release from microsomes into the bulk aqueous phase showed that the pool of estrone within the membrane is the substate for UDP-glucuronyl-transferase. The rate of conjugation of estrone was 6-fold greater than the rate of release of estrone from the membrane into the aqueous phase. Several additional experiments showed that the rate of glucuronidation of estrone did not depend on the amount of estrone in the bulk aqueous phase. It is concluded that the microsomal membrane serves to concentrate nonpolar substrates of UDP-glucuronly-transferase. The phospholipid region of the microsomal membrane also may be a co-factor of UDP-glucuronyltransferase in the sense that binding of estrone to the membrane restricts its orientation in a manner that facilitates catalysis.

Animals↗
PubMed1977

[In vitro metabolism of (6,7-H3)estrone and of (6,7-H3) estradiol by the liver in pregnant guinea pigs].

Slices of pregnant guinea pig liver were incubated with (6,7-3H)estrone and with (6,7-3H)estradiol. Free, glucuro- and sulfo-conjugated fractions were isolated by specific extraction and hydrolysis. The radioactivity distribution in these 3 fractions demonstrated a predominance of conjugated compounds (95% of isolated estrogens) with slightly more glucuro-conjugated than sulfo-conjugated compounds. After isolating estrogens by TLC, we were able to determine estrone and estradiol in these 3 fractions from incubations with 3H-estrone or with 3H-estradiol by means of specific activity recrystallisation. Estriol was determined in glucuro-and sulfo-conjugated fractions after incubation with 3H-estrone as well as in sulfo-conjugated fraction after incubation with 3H-estradiol. Glucuro- or sulfo-conjugated estrone was the predominant estrogen after incubation with 3H-estrone just as after incubation with 3H-estradiol. This led us to conclude to an important 17beta-hydroxysteroid-dehydrogenase activity. The 16alpha-hydroxylastic-activity is weaker since estriol represented only 1,43 % of estrogens isolated after incubation with 3H-estrone and 0.82% after incubation with 3H-estradiol.

17-Hydroxysteroid Dehydrogenases↗
PubMed1976

Estrone and estradiol in patients with cirrhosis of the liver: effects of ACTH and dexamethasone.

To study the influence of the adrenal gland on plasma estrogen levels in male patients with hepatic cirrhosis, estrone and estradiol were measured under a variety of experimental conditions. Compared to controls, estradiol levels were moderately elevated by 26% (P is less than 0.05) in patients with hepatic cirrhosis (28.5 +/- 5.4 vs. 36.0 +/- 4.7 pg/ml plasma; n: 12), whereas estrone levels exhibited a two- to threefold increase under basal conditions (32.5 +/- 5.6 vs. 67.8 +/- 20.8 pg/ml; P is less than 0.01). ACTH application resulted in a striking increase in plasma estrone levels in both patients with hepatic cirrhosis and in normal subjects (61.8 +/- 27.5 vs. 27.3 +/- 7.8 pg/ml). During stimulation with ACTH, estradiol levels showed no significant changes. After suppression of the adrenal gland by dexamethasone administered for 5 days, plasma concentrations of estrone and estradiol were found to be reduced. The absolute decrease of estrone was significantly greater in patients with hepatic cirrhosis than in healthy male subjects (35.5 +/- 12.6 vs. 21.3 +/- 6.0 pg/ml; P is less than 0.05; n: 8). Estrogen values, however, were still high in patients with hepatic cirrhosis after 5 days of dexamethasone administration (37.1 +/- 17.6 pg estrone/ml and 23.9 +/- 3.6 pg estradiol/ml plasma). It is suggested that elevated plasma values of estrogens in this disorder may be derived predominantly from adrenal production. Peripheral conversion of androgens to estrone rather than to estradiol appears to be more effective in sustaining plasma levels of estrogens in patients with hepatic cirrhosis.

Adrenal Glands↗
PubMed1978

The use of specific radioimmunoassays to determine the renal clearance rates of estrone and 17 beta-estradiol during the menstrual cycle.

Specific RIAs requiring ether extraction only were established for estrone and 17 beta-estradiol both in plasma and in urine from the nonpregnant female. These assays were used to measure the renal clearance rates of estrone and of 17 beta-estradiol in eight ambulatory women in the follicular and in the luteal phases of the menstrual cycle. The mean (+/-SE) for the renal clearance rate of estrone was 0.71 +/- 0.058 ml/min in the follicular phase and 1.26 +/- 0.35 ml/min in the luteal phase. The mean (+/-SE) renal clearance rate of 17 beta-estradiol was 0.44 +/- 0.055 ml/min in the follicular phase and 0.29 +/- 0.043 ml/min in the luteal phase. There was no significant difference in the renal clearance rates of either estrone or of 17 beta-estradiol between the follicular and luteal phases of the cycle. The renal clearances of estrone and 17 beta-estradiol were highly correlated (r = 0.84; P less than 0.01). The renal clearance rate of estrone was significantly greater than that of 17 beta-estradiol in both phases of the cycle (P less than 0.01).

Estradiol↗
PubMed1978

[Effect of estrone on rat uterine contraction induced by prostaglandin (author's transl)].

Influence of estrone on uterine contraction and increase of internal pressure of uterus induced by PG were studied in the rat. The sensitivity of the uterus to PG was increased after estrone injection, the maximum effect being observed 72 hours after the administration. Regarding uterine contraction and increase of internal pressure induced by PGE2 or PGF2alpha, the amplitude was enlarged but the frequency was decreased with estrone injection. Contraction and increase of internal pressure induced by PG were well correlated in the rat uterus treated with estrone. Progesterone inhibited the stimulatory action of estrone on uterine contraction induced by PG. These results suggest that estrone may play an important role in action of PG in rat uterus.

Animals↗
PubMed1978

Effects of fracture trauma, estrone treatment, and 2-G environment on the epiphyseal cartilage zones of developing avian radii.

Female birds subjected to closed fracture of the right radius at 2 weeks post-hatching were allowed to heal for 14 d at either earth gravity (1 G) or a 2-G hypergravity state, with saline-injected controls and 0.2- and 0.4-mg estrone (estrogen) treated groups. Animals were sacrificed following the last injection and radii were routinely processed histologically for micrometer measurements of the mid-coronal height and width of the cartilage zones of the proximal and distal epiphyses. Proximal epiphyses of estrone-treated, normo-gravity chicks showed a decreased growth in height of the articular, proliferating, and hypertrophic cartilage zones and an increased interstitial growth of the hypertrophic and calcified layers of estrone-treated, 2-G animals. Growth in height of the cartilage layers of the distal epiphyses of fractured radii was primarily stimulated when estrone-treated chicks were also exposed to the 2-G state. Appositional growth of all cartilage layers of the proximal and distal epiphyses of normo-gravity birds was increased by 0.2 mg estrone. In addition, growth in the width of all cartilage layers of the distal epiphyses of 2-G animals was increased with the administration of 0.4 mg estrone.

Animals↗
PubMed1978

Remodeling of the avian fracture callus by estrone treatment and exposure to a 2 g environment.

Rhode Island Red female chicks were subjected to complete closed fracture of the right radius at two weeks post hatching. The animals were allowed to heal for 2 weeks at either earth gravity (1 g) or a 2 g environment with saline injected controls and estrone injected experimentals. Total fractured bone weight was decreased by exposure to the 2 g environment regardless of whether the animal received saline or estrone treatment. The mean weight of fracture callus was significantly decreased when the hypergravity exposed animals received low hormonal levels of 0.2 mg estrone. The average mid-cross sectional diameter of fracture callus was significantly decreased when the centrifuged chicks received saline or 0.2 mg estrone and it was increased with the administration of high hormonal levels of 0.4 mg to the 2 g animal. The mean thickness of the subperiosteal trabeculae of the bridging callus was decreased by exposure to hypergravity either with or without estrone treatment.

Animals↗