Evidence of formation of isomeric methoximes from 20-oxosteroids

The formation and gas chromatographic behavior of syn- and anti-isomers in position 20 of the methoxime-trimethylsilyl (MO-TMS) derivatives of many 20-oxo and 3,20-dioxo-21-hydroxysteroids is reported. The existence of such isomers was established from the gas chromatographic (GC) and mass spectrometric analysis of the MO-TMS derivatives of 3 alpha,21-dihydroxy-5 beta-pregnan-20-one and its 17 alpha-epimer. The degree of separation during GC analysis of the syn- and anti-isomers in position 20, as well as those in position 3, is associated to the position of additional hydroxyl groups on the steroid ring. These data are very important for the location of oxygenated substituents such as 2 alpha/2 beta, 6 alpha/6 beta, 11 beta, 16 alpha, 17 alpha, 18, 19 or 21-hydroxyl groups during structural studies of 20-oxo and 3,20-dioxosteroids.     

Assay and properties of 18-hydroxylation of endogenous and exogenous corticosterone in rat adrenals. Evidence for heterogeneity of 18-hydroxylase activity.

A mass fragmentographic technique for assay of 18-hydroxylation of labeled (exogenous) and unlabeled (endogenous) corticosterone in adrenal mitochondria and in reconstituted cytochrome P-450 systems has been developed. An extract of an incubation of [14-14C]corticosterone is subjected both to thin-layer radiochromatography and to mass fragmentography (as O-methyloxime-trimethylsilyl ether derivative). In the latter procedure the ions at m/e 605 and 607 (specific for the derivatives of unlabeled and labeled 18-hydroxycorticosterone, respectively), at m/e 591 and 593 (specific for the derivatives of unlabeled labeled aldosterone, respectively) and at m/e 548 and 550 (specific for the derivatives of unlabeled and labeled corticosterone, respectively) were followed through the gas-liquid chromatography. From the ratio between the peaks obtained in the mass fragmentography and from the percentage conversion of [4-14C]corticosterone obtained in the thin-layer radiochromatography, the amount of endogenous and exogenous 18-hydroxycorticosterone and aldosterone could be calculated. The effects of time, enzyme, and substrate concentration of 18-hydroxylation were studied and optimal conditions for assay were determined. Under most conditions, the ratio between labeled and unlabeled 18-hydroxylated products was about constant, indicating that labeled and unlabeled corticosterone were not in equilibrium. It was ascertained that the 18-hydroxycorticosterone and aldosterone formed in the incubations were derived from corticosterone. [4-14C]18-Hydroxydeoxycorticosterone was not converted into aldosterone or 18-hydroxycorticosterone. In vitro studies with different 18-hydroxylase inhibitors (spironolactone, canrenone, and canrenoate-K) and studies with rats pretreated with KCl in drinking fluid suggest that 18-hydroxylation of corticosterone is catalyzed by an enzyme system different from that catalyzing 18-hydroxylation of deoxycorticosterone.     

Tetra- and hexahydro derivatives of aldosterone and 18-hydroxycorticosterone by chemical and microbial reductions

Preparative methods were developed for reduction with NaBH4 at 0 of 3 beta, 5 alpha- and 3 alpha, 5 beta-tetrahydroaldosterone (1) and (12) to their respective 20 alpha-ol derivatives 2a and 13a. Corroboration of structures was obtained by periodate oxidations to the lactols 3b and 14b and thence, by further oxidation, to the lactones 4 and 15 respectively; these lactones were also independently obtained from 1 and 12. Reduction with NaBH4 at 80 degrees C converted 1 and 12 into 18-hydroxy-3 beta, 5 alpha, 20- and 18-hydroxy-3 alpha, 5 beta, 20-hexahydrocorticosterone 6a and 17a respectively, which were mixtures of epimers at C-20. Compound 17a could also be prepared by reduction of the lactone 21 with sodium aluminum bis-(methoxyethoxy) hydride. Again, periodate oxidations of 6a and 17a gave the lactols 7b and 22b and thence, by Jones oxidation, the diketolactones 8 and 23, which were also prepared from 18-hydroxy-11-dehydrocorticosterone (10) and 18-hydroxycorticosterone (24) respectively. Improved conditions for reduction with Clostridium paraputrificum permitted convenient conversion of aldosterone (11), the corresponding 18 leads to 11 lactone 18a and 18-hydroxycorticosterone (24) into their 3 alpha, 5 beta-tetrahydro derivatives.     

The effects of infusions of ring-A-reduced derivatives of aldosterone on the antinatriuretic and kaliuretic actions of aldosterone

Infusion of Ring-A-reduced metabolites of aldosterone in adrenalectomized male rats for 4 days revealed that 5 alpha-Ring-A-reduced derivatives, 5 alpha-dihydroaldosterone (5 alpha-DHAldo; 2.5-5.0 micrograms/day), 3 alpha,5 alpha-tetrahydroaldosterone (3 alpha,5 alpha-THAldo; 5-25 micrograms/day), and 3 beta,5 alpha-THAldo (50-175 micrograms/day) possessed intrinsic Na+-retaining activity. The same infusions of 5 alpha-DHAldo, 3 alpha,5 alpha-THAldo, and 3 beta,5 alpha-THAldo, also lowered the urinary excretion of potassium. The 5 beta-Ring-A-reduced derivative 3 alpha,5 beta-THAldo did not demonstrate either of these biological properties. In another set of experiments, on the fourth day of infusion, aldosterone (0.1 microgram/rat) was administered acutely subcutaneously; none of the Ring-A-reduced derivatives altered the Na+-retaining activity of aldosterone. However, in a dose-dependent manner, both 3 alpha,5 alpha-THAldo and 3 beta,5 alpha-THAldo blunted the urinary K+-secretory effect of aldosterone; low dosages of 5 alpha-DHAldo and larger dosages of 3 alpha,5 beta-THAldo did not. Thus, the 5 alpha-reduced derivatives of aldosterone not only lowered urinary Na+ and K+ excretion in their own right, but two of them blunted the kaliuretic response of the parent mineralocorticoid, aldosterone. Further experiments will be required to determine whether these aldosterone metabolites are further metabolized or interconverted during the expression of the regulatory properties described here and whether these properties are physiologically relevant.     

Quantitative analysis of steroid profiles from urine by capillary gas chromatography : I. Accuracy and reproducibility of the sample preparation

A method is described for the determination of steroid profiles from urine by means of gas chromatography using high-efficiency glass capillary columns. The accuracy and reproducibility of essential steps in the sample preparation (extraction of steroids and steroid conjugates by means of XAD-2, enzymatic hydrolysis with Helix pomatia juice, solvolysis in acidified ethyl acetate and alkali wash) are established using different endogenously labelled urine samples, obtained from normal subjects to whom labelled steroids had been administered. Preliminary results are given on the reproducibility of the derivatization procedure (formation of methoxime-trimethylsilyl (MO-TMS) ethers), the gas chromatographic analysis and the whole method. Two procedures for the purification of MO-TMS steroid derivatives are compared. Application of the method to urine samples of patients with various endocrine disorders is included.     

Synthesis and gas chromatographic-mass spectrometric analysis of reduced compounds derived from 6 alpha- and 6 beta-hydroxy-11-deoxycorticosterone

A series of thirty two 6-hydroxylated steroids were synthesized by selective reduction of the 4-5 double bond, the 3-oxo group, and/or the 20-oxo group of 6 alpha- and 6 beta-hydroxyDOC. The different reactions leading to the production of specific isomers are discussed. The gas chromatographic and spectrometric characteristics of the methoxime-trimethylsilyl (MO-TMS) or trimethylsilyl (TMS) derivatives of the isomers obtained are given. The gas chromatographic separation of the syn- and anti-isomers of the methoxime in position 3 was found to be characteristic of the configuration of the hydroxyl in position 6. The difference between methylene unit values of syn- and anti- isomers is much larger for the 6 alpha-series than for the 6 beta-series. The mass spectral analysis showed that many ions are specific of the MO-TMS derivatives of steroids with 3,6-dihydroxy-4-ene or 3-oxo-6-hydroxy-4-ene structure. In the case of steroids with a saturated ring A no significant ions characteristic of the presence of a 6-trimethylsilyloxy substituent were found. This work provides previously unavailable reference data on 6-hydroxylated steroids which should facilitate the study of corticosteroid metabolism.     

High-performance liquid chromatographic separation of corticosteroids in plasma of rats. Its application to the determination of the circadian rhythm of 18-hydroxycorticosterone related to aldosterone and corticosterone

An efficient separation of corticosteroids in plasma of rats was obtained by reversed-phase high-performance liquid chromatography (HPLC). Plasma corticosteroid assays with HPLC separation were used to determine the circadian rhythm of 18-hydroxycorticosterone (18-OHB) and its possible relationship to aldosterone or corticosterone in conscious rats under standard conditions (regular diet; 12-hour light and 12-hour dark cycle). Significant circadian rhythms of plasma corticosterone, 18-OHB and aldosterone were observed with peak values at 20.00 h and nadir values at 08.00 h. The mean ratio of plasma 18-OHB to aldosterone during 24 h was 2.4. The circadian rhythm of 18-OHB was also correlated with that of plasma aldosterone or corticosterone.     

Determination of aldosterone secretion rate utilizing mixed mode and high performance liquid chromatography

A simpler method for determining aldosterone secretion rate (ASR) has several applications. High performance liquid chromatography (HPLC) has several advantages over traditional chromatographic methods for purification to constant specific activity of aldosterone liberated from its 18-glucuronide by acid hydrolysis. We found it necessary to introduce several modifications to remove urochromes before HPLC. Two methods for determining ASR were developed. With Method A a more traditional initial procedure was followed, and Sephadex LH-20 chromatography allowed removal of considerable urochromes before HPLC. However, aldosterone recovery was improved with Method B, which employed several bonded phase silica derivatives (Sepralytes) and a PBE 94 column to remove urochromes before HPLC. With this procedure the Sephadex LH-20 chromatography was not required. Aldosterone purification to constant specific activity was achieved by HPLC on a diol column with a normal phase system, and quantification was performed by RIA. ASR determinations were equivalent with both methods. This methodology should be applicable to other steroid secretory rate determinations and to applications involving purification of steroid conjugates.     

HPLC isolation and GC-MS characterization of a compound strongly cross reacting with tetrahydroaldosterone antiserum

Urines from patients with hypertension and elevated aldosterone levels, i.e. primary aldosteronism due to adrenal adenoma or hyperplasia or carcinoma were extracted, paper chromatographed and thereafter chromatographed repeatedly with normal phase and repeatedly with reversed phase HPLC systems in an attempt to find new metabolites of aldosterone. Specific 3 alpha-hydroxy-5 beta-tetrahydroaldosterone antiserum was used in a radioimmunoassay system to detect possible aldosterone metabolites in the HPLC fractions after each isolation step. The immunoactive HPLC fractions were derivatized and analysed by GC-MS. A relatively nonpolar compound, 11 beta:18(S),18:20 alpha-diepoxy-5 beta-pregnan-3 alpha-ol, was isolated and identified in this manner. This material was originally described by Kelly et al., in 1962 after loading human subjects with huge amounts (25-160 mg) of exogenous aldosterone. This material has not yet been described from endogenously produced aldosterone. Very small amounts, if any, were similarly isolated from the urine of a control subject. Therefore, this compound could prove to be a new marker for hypertension due to hyper-production of aldosterone.     

Versatile steroid molecules at the end of the aldosterone pathway

18-hydroxycorticosterone converts spontaneously and reversibly to a variety of less polar forms and derivatives, some of which are precursors to aldosterone. In particular, 21-hydroxy-11 beta, 18-oxido-4-pregnene-3,20-dione (18-DAL) is hydroxylated to aldosterone with high yields in the presence of malate and NADP+, at pH 4.8. 18-DAL also behaves as a metabolic intermediate between 18-OH-B and aldosterone according to time-course and trapping experiments. Consequently, the final steps of the aldosterone pathway at pH 4.8 could be identified as 18-OH-B, 18-DAL and aldosterone, in this sequence. The submitochondrial distribution of aldosterone biosynthesis is compatible with this postulate. The work also shows that some forms of 18-OH-B are promoters of hydrogen transport in renal tubuli and that this regulation may be independent of sodium reabsorption. These results suggest a regulatory model, new in steroid biology, according to which steroid molecules bearing an oxidized angular C18-methyl may undergo structural changes between precursor ("P") and hormonal ("H") forms in response to homeostatic requirements.     

Synthesis of 19-hydroxyaldosterone and the 3 beta-hydroxy-5-ene analog of aldosterone, active mineralocorticoids

19-Hydroxyaldosterone (20) and the 3 beta-hydroxy-5-ene analog of aldosterone (HAA) (8) were synthesized from 21-acetoxy-4-pregnene-3,20-dion-20-ethylene ketal-18, 11 beta-lactone (2) as follows: the double bond was transposed from the 4,5 to the 5,6-position by enol acetylation to 3, followed by sodium borohydride reduction. Further reduction of the resulting lactone 4a with diisobutylaluminum hydride (DIBAH) furnished the 20-ketal of HAA 6, from which free HAA (8) and the 18,21-anhydro compound 7 were obtained by acid treatment. The [1H]NMR spectrum of 8 in CDCl3 showed it to be a mixture of two isomeric forms. Correlation with the known aldosterone-gamma-etiolactone (10) was established by periodate oxidation of HAA to the corresponding etiolactone 9 followed by chromic acid oxidation. The preparation of 20 was next effected in the following manner: the diacetate 4b was converted into the 6 beta, 19-oxido compound 13b by addition of hypobromous acid followed by the hypoiodite reaction of the bromohydrin 11. Mild saponification of 13b lead to the corresponding diol 13a, and was followed by selective oxidation to the 3-one 14, readily dehydrobrominated to 15a. Reductive ring opening furnished a mixture of the 19,21-diol 16a and its 5-ene isomer 16b, which was directly converted to the diketal 17. Reduction with DIBAH gave the hemiacetal 18, and hydrolysis of the latter 19-hydroxyaldosterone (20) as a water-soluble solid, accompanied by the 18,21-anhydro compound 19. 19-Hydroxyaldosterone exists in CHCl3 and water as a mixture of mainly two isomers. Periodate oxidation furnished the etiolactone 21. Preliminary results indicate that HAA and 19-hydroxyaldosterone are active mineralocorticoids in the Kagawa bioassay and short-circuit current measurements.     

Differences between adrenal adenoma causing primary aldosteronism and other adrenal tissues in the incorporation of labeled steroid precursors into their products

The incorporation and conversion of several labeled steroid precursors into their products were examined in slices of adrenal tissue from two patients with primary aldosteronism and compared with that in “normal” adrenal tissue and adrenal tissues from a patient with Gushing's syndrome. The products of the incorporation were separated by Sephadex LH-20 column chromatography. The major products of conversion in the adenomatous tissue of primary aldosteronism were 18-hydroxycorticosterone and lesser amounts of aldosterone. Smaller amounts of 18-hydroxycorticosterone were isolated from all other adrenal tissues studied. No aldosterone could be recovered after incubating any of the adrenal tissue studied with labeled 18-hydroxy-11-deoxycorticosterone or 18-hydroxycorticosterone as precursor steroid. These $\text{in vitro}$ results seem to suggest that there is increased 18-hydroxylation in the adenoma of primary aldosteronism compared with other tissues and that relatively more 18-hydroxycorticosterone is produced in such tissue than aldosterone.     

Steroid profiling in the study of rat testicular steroidogenesis

Twenty authentic steroids, derivatized as O-methyl oximes (MO), trimethylsilyl (TMS) ethers or as MO-TMS ethers have been subjected to capillary gas chromatography using two different columns. Virtually all of the steroid derivatives have been resolved, one difficult pair to separate being 5,16-androstadien-3 beta-ol and 5 alpha-androst-16-en-3 beta-ol on the non-selective phase OV-1. Where syn and anti forms of MO derivatives arose, these were also resolved under the conditions utilised. This technique of 'steroid profiling' has been applied to the separation and quantification of metabolites of pregnenolone which were formed during incubations of the microsomal and cytosolic fractions from rat testes. The majority of the metabolites were found in the microsomal incubation. These compounds included some odorous 16-androstenes as well as other C21 and C19 steroids, the formation of which was consistent with the 5-ene and 4-ene pathways of testosterone biosynthesis being operative. In addition, evidence was obtained for 16 alpha-hydroxylation of C21 steroids. Very much less metabolic activity was found in the cytosolic fraction of rat testes. Metabolic pathways have been proposed which both confirm and extend earlier work. We conclude that the rat testis can only form some of the odorous, possibly pheromonal, 16-androstenes and that these are quantitatively less important than in the porcine testis.     

Identification of aldosterone metabolites formed by A6 cells

The A6 cell line of the toad kidney is well known to form an Na+ transporting tight epithelium in culture and is often used as an experimental model for Na+ transport systems. Although it has been shown that A6 cells can convert aldosterone to polar metabolites, these metabolites have not been identified. Therefore, in this study, we tried to identify the metabolites of aldosterone formed by A6 cells in culture. A6 cells at confluence were incubated with serum-free culture media containing [3H]aldosterone. When radioactive compounds in incubation media were separated by reversed phase high-pressure liquid chromatography (HPLC), four fractions (fractions A-D) were obtained. Fraction A, a mixture of two components, comprised the majority of metabolites formed. The more polar material (fraction A-1) and the less polar material (fraction A-2) of fraction A contained 47-71 and 9-19% of total radioactivity, respectively. When incubated in cell-free media, fraction A-2 was found to be unstable and partially converted to fraction A-1. Fraction B, 0.7-1.5% of total radioactivity, and fraction C, 8-21% of total radioactivity, cochromatographed with iso-aldosterone and D-aldosterone, respectively. Fraction D, 4-8% of total radioactivity, was a mixture of two components, which cochromatographed with 3 beta,5 beta-tetrahydroaldosterone and 5 alpha-dihydroaldosterone, respectively. In order to identify fraction A-2 material, large-scale cultures were performed and fraction A-2 was separated and purified by reversed phase HPLC. The purified material was analyzed by fast atom bombardment mass spectrometry and nuclear magnetic resonance spectroscopy. These two procedures unambiguously revealed that this material was 6 beta-hydroxyaldosterone. These results demonstrate that aldosterone can be converted to at least four metabolites by the incubation with A6 cells, and that major metabolites are polar compounds, a portion of which is 6 beta-hydroxyaldosterone.     

Glucocorticoid metabolism and Na+ transport in chicken intestine

The role of aldosterone in regulation of electrogenic Na+ transport is well established, though mineralocorticoid receptors bind glucocorticoids with similar binding affinity as aldosterone and plasma concentration of aldosterone is much lower than glucocorticoids. In mammals, the aldosterone specificity is conferred on the low-selective mineralocorticoid receptors by glucocorticoid inactivating enzyme 11beta-hydroxysteroid dehydrogenase (11HSD) that converts cortisol or corticosterone into metabolites (cortisone, 11-dehydrocorticosterone) with lower affinity for these receptors. The present study examined the chicken intestine, whether changes in 11HSD activity are able to modulate the effect of corticosterone on Na+ transport, and how the metabolism of this hormone is distributed within the intestinal wall. This study shows that not only aldosterone, but also corticosterone (B), was able to increase the electrogenic Na+ transport in chicken caecum in vitro. The effect of corticosterone was higher in the presence of carbenoxolone, an inhibitor of steroid dehydrogenases, and was comparable to the effect of aldosterone. The metabolism of B in the intestine was studied; results showed oxidation of this steroid to 11-dehydrocorticosterone (A) and reduction to 11-dehydro-20beta-dihydrocorticosterone (20diA) as the main metabolic products at low nanomolar concentration of the substrate. In contrast, 20beta-dihydrocorticosterone and 20diA were the major products at micromolar concentration of B. Progesterone was converted to 20beta-dihydroprogesterone. The metabolism of corticosterone was localized predominantly in the intestinal mucosa (enterocytes). In conclusion, the oxidation at position C11 and reduction at position C20 suggest that both 11HSD and 20beta-hydroxysteroid dehydrogenase (20HSD) operate in the chicken intestine and that the mucosa of avian intestine possesses a partly different system of modulation of corticosteroid signals than mammals. This system seems to protect the aldosterone target tissue against excessive concentration of corticosterone and progesterone.     

Gas-liquid chromotography of trimethylsilyl and alkyl oxime-trimethylsilyl derivatives of some prostaglandins

TMS (trimethylsilyl), MO-TMS (methyl oxime-TMS), and EO-TMS (ethyl oxime-TMS) derivatives of several prostaglandins (A, B1, B2, E1, 8-iso-E1, E2 and 8-iso-E2) were prepared and their gas chromatographic properties examined on a moderately polar (OV-17) and a relatively non-polar (SE-30) stationary phase. Combined gas chromatography-mass spectrometry (GC-MS) using an LKB 9000 instrument was used to identify the different derivatives. Although the TMS derivatives are more easily prepared, the TMS derivatives of the PgE series are thermally somewhat unstable. Thus, MO-TMS and EO-TMS derivatives which exhibit more regular retention increments are more useful for analytical work. The EO-TMS derivatives may be useful in determining mass spectral fragmentation modes of the prostaglandin derivatives.     

Isolation of aldosterone synthase cytochrome P-450 from zona glomerulosa mitochondria of rat adrenal cortex

A cytochrome P-450 capable of producing aldosterone from 11-deoxycorticosterone was purified from the zona glomerulosa of rat adrenal cortex. The enzyme was present in the mitochondria of the zona glomerulosa obtained from sodium-depleted and potassium-repleted rats but scarcely detected in those from untreated rats. It was undetectable in the mitochondria of other zones of the adrenal cortex from both the treated and untreated rats. The cytochrome P-450 was distinguishable from cytochrome P-45011 beta purified from the zonae fasciculata-reticularis mitochondria of the same rats. Molecular weights of the former and the latter cytochromes P-450, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, were 49,500 and 51,500, respectively, and their amino acid sequences up to the 20th residue from the N terminus were different from each other at least in one position. The former catalyzed the multihydroxylation reactions of 11-deoxycorticosterone giving corticosterone, 18-hydroxydeoxycorticosterone, 18-hydroxycorticosterone, and a significant amount of aldosterone as products. On the other hand, the latter catalyzed only 11 beta- and 18-hydroxylation reactions of the same substrate to yield either corticosterone or 18-hydroxydeoxycorticosterone. Thus, at least two forms of cytochrome P-450, which catalyze the 11 beta- and 18-hydroxylations of deoxycorticosterone, exist in rat adrenal cortex, but aldosterone synthesis is catalyzed only by the one present in the zona glomerulosa mitochondria.     

Potential early intermediates in anaerobic benzoate degradation by Rhodopseudomonas palustris.

Alkali-treated extracts of Rhodopseudomonas palustris growing photosynthetically on benzoate were examined by gas chromatography/mass spectrometry for partially reduced benzoate derivatives. Two cyclic dienes, cyclohexa-2,5-diene-1-carboxylate and cyclohexa-1,4-diene-1-carboxylate, were detected. Either compound supported cell growth as effectively as benzoate. These results suggest that these cyclohexadienecarboxylates, probably as their coenzyme A esters, are the initial reduction products formed during anaerobic benzoate metabolism by R. palustris.     

The effects of the licorice derivative, glycyrrhetinic acid, on hepatic 3 alpha- and 3 beta-hydroxysteroid dehydrogenases and 5 alpha- and 5 beta-reductase pathways of metabolism of aldosterone in male rats

Ingestion of licorice or treatment with chemical derivatives of glycyrrhetinic acid (GA), an active principle of licorice, can cause hypertension, sodium retention, and hypokalemia. Although GA has been shown to inhibit 11 beta-hydroxysteroid dehydrogenase, it may not be the only hepatic enzyme affected by this licorice derivative. Therefore, we studied the effects of GA on other major hepatic steroid-metabolizing enzymes from adrenalectomized male rats using aldosterone as the substrate; namely, delta 4-5 alpha- and delta 4-5 beta-reductases and 3 alpha- and 3 beta-hydroxysteroid dehydrogenases (3 alpha- and 3 beta-HSD). From these in vitro studies, we demonstrated that GA does not affect either microsomal 5 alpha-reductase or cytosolic 3 alpha-HSD activity. However, GA is a potent inhibitor of cytosolic 5 beta-reductase; the K(is) and K(ii) were calculated from enzyme kinetic analysis to be 6.79 and 5.41 microM, respectively, using the Cleland equation, indicating that GA is a noncompetitive inhibitor of aldosterone. In addition, GA specifically inhibited microsomal 3 beta-HSD enzyme activity by what appears to be a competitive inhibition mechanism, causing a build-up of the intermediate, 5 alpha-dihydroaldosterone (DHAldo). Thus, this study has indicated that GA has a profound effect on hepatic ring A-reduction of aldosterone. Inhibition of 5 beta-reductase and 3 beta-HSD results in decreased synthesis of both 3 alpha, 5 beta-tetrahydroaldosterone (THAldo) and 3 beta, 5 alpha-THAldo and, hence, accumulation of aldosterone and 5 alpha-DHAldo, both potent mineralocorticoids.(ABSTRACT TRUNCATED AT 250 WORDS)     

Potential early intermediates in anaerobic benzoate degradation by Rhodopseudomonas palustris.

Alkali-treated extracts of Rhodopseudomonas palustris growing photosynthetically on benzoate were examined by gas chromatography/mass spectrometry for partially reduced benzoate derivatives. Two cyclic dienes, cyclohexa-2,5-diene-1-carboxylate and cyclohexa-1,4-diene-1-carboxylate, were detected. Either compound supported cell growth as effectively as benzoate. These results suggest that these cyclohexadienecarboxylates, probably as their coenzyme A esters, are the initial reduction products formed during anaerobic benzoate metabolism by R. palustris.