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At least 19 recordsLinked to original sources
PubMed1975

Chemical modification of amino acid residues associated with the delta-4-3-ketosteroid-dependent photoinactivation of delta-5-3-ketosteroid isomerase.

The photoinactivation of the Δ (5)-3-ketosteroid isomerase of Pseudomonas testosteroni in the presence of 3-oxo-4-estren-17β-yl acetate and air is accompanied by destruction of histidine and aspartate (or asparagine). The first order rate constant of photoinactivation of the enzyme is equal, within experimental error, to the first order rate constant for the destruction of a single aspartate (or asparagine) residue and is considerably greater than the first order rate constant for the destruction of a single residue of histidine. When the photolysis is carried out under anaerobic conditions, only aspartic acid (or asparagine) is destroyed as enzyme is inactivated. Both inactivation and aspartate (or asparagine) destruction occur to a greater extent in the absence of oxygen than in its presence. The destruction of histidine, on the other hand, is found to be strictly oxygen-dependent. These results suggest that photochemical modification of a single residue of aspartate (or asparagine) is largely, if not entirely, responsible for photoinactivation of the enzyme under these conditions. When irradiated in the presence of 3-oxo-4-entren-17β-yl acetate, performic acid-oxidized bovine pancreatic ribonuclease does not suffer any detectable destruction of its aspartic or asparaginyl residues but does undergo significant destruction of its histidine residues. These observations suggest that the aspartate (or asparagine) residue modification found with isomerase is an active site-directed photochemical reaction, whereas the modification of histidine may not be.

Amino Acids↗
PubMed1990

Purification and characterization of 3-ketosteroid-delta 1-dehydrogenase from Nocardia corallina.

The inducible 3-ketosteroid-delta 1-dehydrogenase of Nocardia corallina which catalyzes the introduction of a double bond into the position of carbon 1 and 2 of ring A of 3-ketosteroid has been obtained in four steps with a 50% yield and 360-fold purification. The enzyme is homogeneous as judged by SDS-gel electrophoresis and is a monomeric protein with a molecular weight of 60,500. The isoelectric point of the enzyme is about 3.1. The enzyme contains 1 mol of flavin adenine dinucleotide per mol of protein, and has a typical flavoprotein absorption spectrum with maxima of 458, 362 and 268 nm. The enzyme is very stable in the absence of added cofactors, and catalyzes the dehydrogenation of delta 4-3-ketosteroids in the presence of phenazine methosulfate, which acts as an excellent electron acceptor. Potassium ferricyanide and cytochrome c did not act as electron acceptors. The delta 1-dehydrogenation was also stimulated by molecular oxygen with stoichiometric production of hydrogen peroxide and delta 1,4-3-ketosteroid. The optimum pH is 10 for dehydrogenation using phenazine methosulfate, and is between 8.5 and 10 for the oxidase reaction. The enzyme oxidizes a wide variety of 3-ketosteroids, but not 3 beta-hydroxysteroids. 3-Ketosteroids having an 11 alpha- or 11 beta-hydroxyl group were oxidized at slow rates. The purified enzyme catalyzes efficiently aromatization of the A-ring of 19-nortestosterone and 19-norandrostenedione to produce estradiol and estrone. 19-Hydroxytestosterone, 19-hydroxyandrostenedion and 19-oxotestosterone were converted to the respective phenolic steroids with cleavage of the C10 side-chain. Activities of 3-ketosteroid-delta 4-dehydrogenase, delta 5-3-ketosteroid-4,5-isomerase, 3 beta-hydroxysteroid dehydrogenase and 17 beta-hydroxysteroid dehydrogenase were not observed in the purified preparations. Properties of this novel flavoprotein enzyme are discussed.

Amino Acids↗
PubMed1992

Human ovarian 17-ketosteroid oxidoreductase: unique characteristics of the granulosa-luteal cell and stromal enzyme.

OBJECTIVES: We attempted to test the hypothesis that distinct forms of the 17-ketosteroid oxidoreductase exist in the human ovary and to compare its activity in stroma obtained from normally cycling women and from hyperandrogenic women. STUDY DESIGN: Human ovarian granulosa-luteal cell and stromal 17-ketosteroid oxidoreductase were examined in cell incubations and subcellular homogenates. RESULTS: In subcellular homogenates of granulosa-luteal cells 17-ketosteroid oxidoreductase activity was greater in the cytosol fraction than in the membrane fraction. In contrast, in homogenates of both ovarian stroma and Leydig cells its activity was greater in the membrane fraction than in the cytosol fraction. At the substrate concentrations used estrone was a better substrate than androstenedione for the granulosa-luteal cell 17-ketosteroid oxidoreductase. In contrast, androstenedione was a better substrate than estrone for that in ovarian stromal and Leydig cell membranes. In incubations of ovarian stroma from hyperandrogenic women, significantly more testosterone accumulated in the medium per milligram of tissue than in the medium of incubations of ovarian stroma from normally cycling women (142 +/- 48 vs 7.9 +/- 7.5 pg testosterone per milligram of tissue per 48 hours, mean +/- SD, p less than 0.05). The ratio of testosterone to androstenedione was significantly higher in the medium of incubations of ovarian stroma from hyperandrogenic women than in that from normally cycling women (0.61 vs 0.25, mean, p less than 0.05). The ratio of serum testosterone to androstenedione was significantly greater in hyperandrogenic women than in normally cycling control women (0.31 +/- 0.11 vs 0.20 +/- 0.03, mean +/- SD, p less than 0.05). CONCLUSION: The localization (cytosol fraction) and substrate specificity (estrone) of the granulosa-luteal cell 17-ketosteroid oxidoreductase enzyme resembles that seen in human placenta. The localization (membrane fraction) and substrate specificity (androstenedione) of the ovarian stromal 17-ketosteroid oxidoreductase enzyme resembles that seen in Leydig cells. It may be one enzyme that exists in multiple forms or it may be two (or more) enzymes. In some hyperandrogenic women the ovarian stromal 17-ketosteroid oxidoreductase may be more active than in normally cycling women, contributing to an abnormally increased testosterone production rate.

17-Hydroxysteroid Dehydrogenases↗
PubMed1979

Effect of dexamethasone and ACTH on the secretion pattern of fractionated 17-ketosteroids in hirsutism.

Urinary steroid fractionations of 17-ketosteroids were carried out in 3 normally-ovulating young women and in 2 women with hirsutism. Dehydroepiandrosterone, aetiocholanolone, androsterone, 11 beta-hydroxyaetiocholanolone, 11 beta-hydroxyandrosterone, 11-oxoaetiocholanolone and 11-oxondrosterone were determined quantitatively by paper chromatography. Both patients had decreased levels of 11-deoxy and 11-oxy-17-ketosteroids compared with the normals. The ready suppression of 11-oxy-17-ketosteroids and the poor suppression of 11-deoxy-17-ketosteroids by dexamethasone in both patients suggests an ovarian origin of 11-deoxy-17-ketosteroids. Supporting evidence for an ovarian origin in Case 1 was furnished by the poor suppression of testosterone by dexamethasone and lack of response to ACTH stimulation of the adrenal glands. The presented data emphasize that the precursor of 11-deoxy-17-ketosteroids of ovarian origin, possibly testosterone, may well be the cause of hirsutism in both patients.

17-Ketosteroids↗
PubMed1976

Distinct testicular 17-ketosteroid reductases, one in interstitial tissue and one in seminiferous tubules. Differential modulation by testosterone and metabolites of testosterone.

The final step in the biosynthesis of testosterone is the reduction of androstenedione, which is catalyzed by the microsomal enzyme 17-ketosteroid reductase. Evidence is presented which suggests that there are two distinct 17-ketosteroid reductases in rat testes, one in interstitial tissue and one in seminiferous tubules. The two enzymes have different pH optima, 5.6 for the one from interstitial tissue and 6.5 for the one from seminiferous tubules. At the optimum pH, a 70-fold difference in Km values was observed, 17 muM for the interstitial tissue enzyme and 0.25 muM for the enzyme from seminiferous tubules. Testosterone and metabolites of testosterone have very different effects of each of these enzyme activities. The interstitial tissue enzyme activity is inhibited by testosterone and several 5alpha-reduced metabolites of testosterone and by estrogens. The most potent inhibitor of the steroids investigated was 5alpha-androstane-3alpha, 17beta-diol, followed by 17beta-estradiol approximately equal to dihydrotestosterone greater than testosterone greater than estrone greater than estriol. 5alpha-Androstane-3alpha, 17beta-diol and 17beta-estradiol were shown to act by competitive inhibition with apparent Ki values of 2.2 and 3.7 muM, respectively. In contrast, it was demonstrated that among the above steroids, only dihydrotestosterone inhibits the 17-ketosteroid reductase activity of seminiferous tubules and this inhibition was only observed at very high concentrations of inhibitor. Testosterone stimulated the 17-ketosteroid reductase activity of seminiferous tubules. 5alpha-Androstane-3alpha, 17beta-diol at low concentrations stimulated the enzyme activity from seminiferous tubules, while it had no effect at high concentrations. The remainder of the steroids tested had no effect on the 17-ketosteroid reductase activity of seminiferous tubules. The difference in response of the two enzyme activities suggests a mechanism for local regulation of testosterone synthesis in each testicular compartment that does not involve directly pituitary gonadotropins.

17-Ketosteroids↗
PubMedDate not supplied

Urinary 17-ketosteroid fractions in young patients with breast cancer.

The main fractions of 17-ketosteroids were estimated in 30 young women (under 40 years) with breast cancer and 20 controls of the same age. The determination of the fractionated ketosteroids was made by thin layer chromatography on silicagel. The mean levels of etiocholanolone, androsterone, total ketosteroids and the sum of the fractions of 17-ketosteroids were significantly decreased in patients with breast cancer in comparison with the controls. No significant differences between the mean levels of dehydroepiandrosterone and 11-oxygenated-17-ketosteroids were noted in these groups.

17-Ketosteroids↗
PubMed1977

Correlation of the effects of dexamethasone administration on urinary 17-ketosteroid and serum androgen levels in patients with hirsutism.

Total 24 hour urinary 17-ketosteroid and serum testosterone (T), androstenedione (delta), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DS), and cortisol levels were measured before and during four days of dexamethasone administration in 28 hirsute patients and 10 women with normal ovulatory cycles. Both the base-line urinary 17-ketosteroids and serum androgen levels were significantly higher (p less than 0.05) in hirsute than in normal subjects. Cortisol levels were similar in the two groups. Dexamethasone administration resulted in a significant suppression (p less than 0.05) of all the urinary and serum androgen and cortisol levels in both groups. At the end of suppression the serum DHEA, DS and cortisol levels were similar, while the urinary 17-ketosteroids and serum T and delta levels were still significantly higher (p less than 0.05) in the hirsute than in normal women. There was poor correlation between total urinary 17-ketosteroid and serum androgen results. These finding suggest there is a dual abnormality of androgen production in hirsute patients. The adrenal glands appear to secrete increased quatities of DHEA and DA, while the ovaries appear to produce elevated amounts of T and delta.

17-Ketosteroids↗
PubMed1990

Combined effects of two mutations of catalytic residues on the ketosteroid isomerase reaction.

delta 5-3-Ketosteroid isomerase (EC 5.3.3.1) catalyzes the isomerization of delta 5-3-ketosteroids to delta 4-3-ketosteroids by a conservative tautomeric transfer of the 4 beta-proton to the 6 beta-position with Tyr-14 as a general acid and Asp-38 as a general base [Kuliopulos, A., Mildvan, A. S., Shortle, D., & Talalay, P. (1989) Biochemistry 28, 149-159]. Primary, secondary, and combined deuterium kinetic isotope effects establish concerted substrate enolization to be the rate-limiting step with the wild-type enzyme [Xue, L., Talalay, P., & Mildvan, A. S. (1990) Biochemistry 29, 7491-7500]. The product of the fractional kcat values resulting from the Y14F mutation (10(-4.7)) and the D38N mutation (10(-5.6)) is comparable (10(-10.3)) to that of the double mutant Y14F + D38N (less than or equal to 10(-10.4)) which is completely inactive. Hence, the combined effects are either additive or synergistic. Quantitatively, similar effects of the two mutations on kcat/KM are found in the double mutant. Despite its inactivity, the Y14F + D38N double mutant forms crystals indistinguishable in form from those of the wild-type enzyme, tightly binds steroid substrates and substrate analogues, and immobilizes a spin-labeled steroid in an orientation indistinguishable from that found in the wild-type enzyme, indicating that the double mutant is otherwise largely intact. It is concluded that the total enzymatic activity of ketosteroid isomerase probably results from the independent and concerted functioning of Tyr-14 and Asp-38 in the rate-limiting enolization step, in accord with the perpendicular or antarafacial orientation of these two residues with respect to the enzyme-bound substrate. Synergistic effects of mutating two residues on kcat and on kcat/KM of enzyme-catalyzed multistep reactions are shown, theoretically, to occur when both residues act independently in the same step, and simple additivity occurs when this step is rate-limiting. Other conditions for additivity of the effects of mutations of kcat and kcat/KM are theoretically explored.

Binding Sites↗
PubMedDate not supplied

17-Ketosteroids in leprosy.

Urinary 17-ketosteroids were estimated in 29 lepromatous leprosy cases. Correlation between 17-ketosteroid values, histopathologic findings, and serum G.G.P.T. values is discussed. Low values of 17-ketosteroids were associated with definite leproma to liver indicating the value of liver damage to 17-ketosteroids. This was more marked in males than in females.

17-Ketosteroids↗
PubMed1976

Simple determination of 3alpha-hydroxy fraction and 3beta-hydroxy fraction of urinary 17-ketosteroids.

We describe a method for determination of the 3alpha-hydroxysteroid fraction and 3beta-hydroxysteroid fraction of 17-ketosteroids in urine. The method includes enzymatic hydrolysis with beta-glucuronidase and extraction with ethyl acetate and color development of 3beta-hydroxysteroids by 3beta-hydroxysteroid oxidase and of total 17-ketosteroids by the Zimmermann reaction. The value for 3alpha-hydroxysteroids is calculated by subtracting the value for 3beta-hydroxysteroids from the value for total 17-ketosteroids. Recovery was assessed and results compared with those by an accepted method. Results were satisfactory for measuring these fractions of 17-ketosteroids.

17-Ketosteroids↗
PubMed1976

Mass spectra of delta 4- and 5 alpha-3-ketosteroids formed during the oxidation of some 3 beta-hydroxysteroids by cholesterol oxidase.

Thirty-six delta5- and 5'alpha-3beta-hydroxysteroids have been oxidized with cholesterol oxidase to give the corresponding delta4- and 5alpha-3-ketosteroids, respectively. The mass spectral characteristics of the products (or their trimethylsilyl ether derivatives, in the case of 3-keto-hydroxysteroids) varied considerably, depending especially on the nature of the C-17 sidechain. The ion of m/e 124 (or its equivalent) from cleavage of ring B was frequently a major fragment from delta4-3-ketosteroids, but in some instances was of insignificant abundance. Trimethylsilylation of the product of the oxidation of neoergosterol gave neoergosterone enol-trimethylsilyl ether. Fragmentations of the sidechain predominated in the mass spectra of the 5alpha-3-ketosteroids.

Cholesterol↗
PubMed1975

[17-ketosteroids in the 24-hour urine of miners with vibration disease from local vibration exposure].

The 17-ketosteroid level in the urine secreted in 24 hours s studied in miners with vibration disease. The case material is analyzed according to age, working service, clinical syndromes and stage. It is demonstrated that the continuous effect of local vibrations lead to inhibition of the adrenal function, manifested by a 17-ketosteroids fall. Such a lowering is assumed as one of the adaptational syndrome-manifestations. Regulation of corticosteroid secretion is discussed in the light of complex interrelations--neuroendocrine, biochemical and homeostatic. The role played by oxidation processes is also emphasized. 17-ketosteroids content in the urine has certain diagnostical value, irrespective of the fact that its lowering is by no means a specific manifestation of the vibration disease.

17-Ketosteroids↗
PubMed1992

Substrate polarization by residues in delta 5-3-ketosteroid isomerase probed by site-directed mutagenesis and UV resonance Raman spectroscopy.

delta 5-3-Ketosteroid isomerase (KSI: EC 5.3.3.1) of Pseudomonas testosteroni catalyzes the isomerization of delta 5-3-ketosteroids to delta 4-3-ketosteroids by the stereospecific transfer of the steroid 4 beta-proton to the 6 beta-position, using Tyr-14 as a general acid and Asp-38 as a base. Ultraviolet resonance Raman (UVRR) spectra have been obtained for the catalytically active double mutant Y55F + Y88F, which retains Tyr-14 as the only tyrosine residue (referred to as the Y14(0) mutant), and the Y14F mutant, which has 50,000-fold lower activity. The UVRR results establish that binding of the product analog and competitive inhibitors 19-nortestosterone or 4-fluoro-19-nortestosterone to the Y14(0) mutant does not result in the formation of deprotonated Tyr-14. The UVRR spectra of the steroid inhibitors show large decreases in the vinyl and carbonyl stretching frequencies on binding to the Y14(0) enzyme but not on binding to the Y14F enzyme. These changes cannot be mimicked by protonation of the steroids. For 19-nortestosterone, the vinyl and carbonyl stretching frequencies shift down (with respect to the values in aqueous solution) by 18 and 27 cm-1, respectively, on binding to Y14(0) KSI. It is proposed that the changes in the steroid resonance Raman spectrum arise from polarization of the enone moiety via the close proximity of the charged Asp-38 side chain to the vinyl group and the directional hydrogen bond between Tyr-14 and the 3-carbonyl oxygen of the steroid enone. The 230-nm-excited UVRR spectra do not, however, show changes that are characteristic of strong hydrogen bonding from the tyrosine hydrogen. It is proposed that this hydrogen bonding is compensated by a second hydrogen bond to the Tyr-14 oxygen from another protein residue. UVRR spectra of the Y14(0) enzyme obtained using 200 nm excitation show enhancement of the amide II and S Raman bands. The secondary structure of KSI was estimated from the amide II and S intensities and was found to be low in alpha-helical structure. The alpha-helix content was estimated to be in the range of 0-25% (i.e., 10 +/- 15%).

Binding, Competitive↗
PubMed1990

Dehydroepiandrosterone and estrone 17-ketosteroid reductases in MCF-7 human breast cancer cells.

The identification of several steroid-transforming enzymes within human breast cancers has led to speculation that the growth of some hormone-responsive tumors might be mediated in part by intracellularly derived estrogens. Reports that MCF-7 human breast cancer cells can transform both estrone (E1)1 to estradiol (E2) and dehydroepiandrosterone (DHEA) to the estrogenic steroid 5-androstenediol (AED), have prompted us to investigate the 17-ketosteroid reductase activities (17-KSR's) which mediate these potentially important reactions. Enzyme assays were performed by quantifying the amounts of [3H]AED or [3H]E2 former from [3H]DHEA or [3H]E1, respectively, by various subcellular preparations from MCF-7 cells under a variety of experimental conditions. DHEA 17-KSR was found to be localized exclusively within cytosol, whereas the E1 17-KSR activity appeared to be nearly equally divided between the soluble and particulate cytoplasmic subfractions. The particulate E1 17-KSR appeared capable of utilizing NADH or NADPH, whereas both the cytosolic form of this enzyme and the soluble DHEA 17-KSR activity showed a strict requirement for NADPH. Although both of the soluble 17-KSR's also showed similar pH optima, several other features suggested that they are different enzymes in MCF-7. E1 did not inhibit the conversion of DHEA to AED, and DHEA did not interfere with the transformation of E1 to E2, indicating that major differences in substrate specificity exist between the two cytosolic activities. Furthermore, DHEA 17-KSR activity within cytosol stored at -20 degrees C deteriorated almost completely over twelve weeks of storage, whereas E1 17-KSR activity remained stable. Finally, although both enzymes were found to be subject to product inhibition, AED inhibited DHEA 17-KSR competitively, whereas cytosolic E1 17-KSR activity was inhibited by E2 in noncompetitive fashion. Studies of the oxidation of E2 to E1 by MCF-7 cells showed that this transformation is catalyzed by both soluble and particulate 17-hydroxysteroid oxidases which utilize either NAD or NADP as cofactor. Having previously reported the presence of a particulate NADP(H)-linked androstenedione (AE) 17-ketosteroid oxidoreductase in MCF-7, we now suggest that at least three different enzymes, one particulate and two soluble forms, participate in the conversion of 17-ketosteroids to their hormonally active 17-hydroxysteroid derivatives within this cell line. The restricted substrate requirements of each enzyme provide a rationale for developing selective enzyme inhibitors which could provide important investigational tools and potentially effective therapeutic agents.

17-Hydroxysteroid Dehydrogenases↗
PubMed1990

Studies of the mechanism of the delta 5-3-ketosteroid isomerase reaction by substrate, solvent, and combined kinetic deuterium isotope effects on wild-type and mutant enzymes.

delta 5-3-Ketosteroid isomerase (EC 5.3.3.1) catalyzes the isomerization of delta 5-3-ketosteroids to delta 4-3-ketosteroids by a conservative tautomeric transfer of the 4 beta-proton to the 6 beta-position using Tyr-14 as a general acid and Asp-38 as a general base [Kuliopulos, A., Mildvan, A. S., Shortle, D., & Talalay, P. (1989) Biochemistry 28, 149]. On deuteration of the 4 beta-position (97.0%) of the substrate, kcat(H)/kcat(4 beta-D) is 6.1 in H2O and 6.3 in D2O. The solvent isotope effect, kcat(H2O)/kcat(D2O), is 1.6 for both the 4 beta-H and 4 beta-D substrates. Mutation of Tyr-55 to Phe lowers kcat 4.3-fold; kcat(H)/kcat/4 beta-D) is 5.3 in H2O and 5.9 in D2O, and kcat(H2O)/kcat(D2O) with the 4 beta-H and 4 beta-D substrates is 1.5 and 1.7, respectively, indicating concerted general acid-base catalysis in either the enolization or the ketonization step of both the wild-type and the Tyr-55----Phe (Y55F) mutant enzymes. An additional slow step occurs with the Y55F mutant. Smaller isotope effects on Km are used to estimate individual rate constants in the kinetic schemes of both enzymes. On deuteration of the 4 alpha-position (88.6%) of the substrate, the secondary isotope effect on kcat/Km corrected for composition is 1.11 +/- 0.02 with the wild-type enzyme and 1.12 +/- 0.02 with the Y55F mutant. These effects decrease to 1.06 +/- 0.01 and 1.07 +/- 0.01, respectively, when the 4 beta-position is also deuterated, thereby establishing these to be kinetic (rather than equilibrium) secondary isotope effects and to involve a proton-tunneling contribution. Deuteration of the 6-position of the substrate (92.0%) produces no kinetic isotope effects on kcat/Km with either the wild-type (1.00 +/- 0.01) or the Y55F mutant (1.01 +/- 0.01) enzyme. Since a change in hybridization from sp3 to sp2 occurs at C-4 only during enolization of the substrate and a change in hybridization at C-6 from sp2 to sp3 occurs only during reketonization of the dienol intermediate, enolization of the substrate constitutes the concerted rate-limiting step. Concerted enolization is consistent with the right angle or antarafacial orientations of Tyr-14 and Asp-38 with respect to the enzyme-bound substrate and with the additive effects on kcat of mutation of these catalytic residues [Kuliopulos, A., Talalay, P., & Mildvan, A. S. (1990) Biophys. J. 57, 39a].

Deuterium↗
PubMed1977

Relationship between the soluble glutathione-dependent delta 5-3-ketosteroid isomerase and the glutathione S-transferases of the liver.

Soluble, glutathione-stimulated delta 5-3-ketosteroid isomerase (EC 5.3.3.A) activity of human and rat liver resides in very basic proteins with molecular weights of about 45,000 which are present in high concentrations in these tissues. Physiochemical and immunological evidence is presented for the identity of the proteins responsible for this enzymatic activity with the glutathione S-transferases (RX:glutathione R-transferase, EC 2.5.1.18) that conjugate glutathione with a variety of electrophilic compounds. In the rat, the steroid isomerase is associated principally with the major transferase (B), which is also known as ligandin, and has the versatility to bind various hydrophobic compounds such as bilirubin, corticosteroids, and metabolites of a number of carcinogens. Other rat liver-glutathione S-transferase species are far less active in the steroid isomerization reaction. The delta 5-3-ketosteroid isomerase activity of human liver is more uniformly distributed among the five glutathione S-transferases that have been described. Steroid isomerization differs fundamentally from other reactions promoted by glutathione S-transferases in that glutathione is not consumed in the reaction. However, because the transferase enzymes promote nucleophilic attack by glutathione on a variety of largely foreign organic substrates, a similar mechanism may be involved in the isomerase reaction. Delta 5-3-ketosteroids are among the few known naturally occurring substrates for these enzymes.

Animals↗
PubMed1978

Laboratory medicine. Series on clinical testing. 2. Fractionation of urinary ketosteroids. Procedure and clinical significance.

Ketosteroids, the excretory metabolities of adrenal and gonadal steroids, can be analyzed individually in urine by a simple extraction procedure followed by separation and quantitation by the use of gas/liquid chromatography. The ketosteroids quantitatively detected by the technique are androsterone, etiocholanolone, dehydroepiandrosterone, 11-hydroxyandrosterone, 11-hydroxyetiocholanolone, 11-ketandrosterone, and 11-ketoetiocholanolone. Other steroid metabolities detected are pregnanediol, pregnanetriol, delta5-pregnenetriol, and 11-ketopregnanetriol. In comparison with concentrations of these steroids observed in urine specimens collected from healthy individuals, abnormal results occur in specimens from patients with testicular disease, Cushing's syndrome, adrenal hyperplasia, and several types of female hirsutism. Characteristic profiles for each of these diseases are presented.

11-Hydroxycorticosteroids↗
PubMedDate not supplied

Urinary 17-ketosteroids in diabetic and non-diabetic pregnancies.

The excretion of estriol into the maternal urine is an effective means of evaluating the fetus in pregnancies complicated by a number of metabolic disorders, such as chronic hypertension, renal disease, pre-eclampsia, etc. It is generally used in the management of pregnancies complicated by maternal diabetes mellitus even though some question has been raised as to its validity for this disorder. In this study we have evaluated estriol precursors in the form of 17-ketosteroids in the urine of pregnant women with mild diabetes mellitus as well as a non-diabetic control group. Urinary total estrogen excretion was also determined. Diabetics were found to excrete significantly higher amounts of 17-ketosteroids than the non-diabetic group. The possible significance of this finding in relation to the dynamics of estriol production in pregnancy is discussed.

17-Ketosteroids↗