A Three-Step Route to a Tricyclic Steroid Precursor

ABSTRACT A new model for the perfusion of human term-placentas has been developed for studies on the placental biogenesis of C-18 and C-19 steroids. For viability criteria, the glucose- and oxygen-consumption, regional perfusion control by dye-infusions or scanning after injection of 99Tc-labelled macroparticles, and the histological qualification were chosen. The recycled perfusate was investigated for the steroids oestrone (Oe1), oestradiol-17β (Oe2), oestriol (Oe3), 4-androstene-3,17-dione (A), testosterone (T), and human placental lactogen (HPL) by radioimmunoassay in controls and perfusions with the foetal steroid precursor dehydroepiandrosterone sulphate (DHA-S). In control perfusions, steroid hormones were found in constant ratios (Oe1:Oe2:Oe3:T:A = 30:1.5:100:0.35:1). Following the administration of 10 mg DHA-S for testing the metabolic capacity of the organ, high concentrations of Oe1 (90–720 ng/ml = 250–3970 % as compared to 100% pre-injection values) were found, shortly preceded by a rapid increase of A (66–1000 ng/ml = 100–16 000 %). A typical surge of T (5.3–147 ng/ml = 265–4640 %) preceded the normally slower increment of Oe2 (22–220 ng/ml = 1570–4330 %). The concentrations of Oe3 and HPL remained nearly unchanged. From different steroid patterns after DHA-S-load, two distinct responses of term-placentas could be differentiated: Group I (n=12) showed high concentrations of Oe1 (3200 ± 940 %), a small increase of T (1020 ± 500%), as well as low and delayed values of Oe2 (1660 ± 450%). In Group II (n = 5), values were high for T (3160 ± 1020%) and Oe2 (3300 ± 1110%), whereas Oe1 was found in a lower range (508 ± 302%). In contrast to in vivo findings in maternal venous blood after DHS-S injection to the mother, oestrone was found in perfusions as the main oestrogen fraction from DHA-S. Thus, the analysis of such metabolic differences might be of help in the interpretation of complex results from the DHA-S-loading test.

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Receptor-mediated gonadotropin action in the ovary Demonstration of acute dependence of rat luteal cells on exogenously supplied steroid precursor (sterols) for gonadotropin-induced steroidogenesis

Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism ◽

10.1016/0005-2760(81)90248-4 ◽

1981 ◽

Vol 665 (3) ◽

pp. 362-375 ◽

Cited By ~ 18

Author(s):

Salman Azhar ◽

Mangaladevi Menon ◽

K.M.J. Menon

Keyword(s):

Luteal Cells ◽

Acute Dependence ◽

Steroid Precursor

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SUBSTRATE CARRIERS FOR C-1(2)-DEHYDROGENATION OF 6-METHYLENE ANDROSTENEDIONE TO EXEMESTANE BY GROWING AND IMMOBILIZED ARTHROBACTER SIMPLEX NCIM 2449

Asian Journal of Pharmaceutical and Clinical Research ◽

10.22159/ajpcr.2017.v10i2.15861 ◽

2017 ◽

Vol 10 (2) ◽

pp. 392

Author(s):

Prachi Patil ◽

Rajesh Sharma ◽

Tushar Banerjee ◽

Shridhar Patil

Keyword(s):

Soybean Oil ◽

Organic Solvents ◽

Time Course ◽

Shake Flask ◽

Immobilized Cells ◽

Critical Factor ◽

Tween 80 ◽

Arthrobacter Simplex ◽

Steroid Precursor ◽

Ca Alginate

Objective: Permeability of hydrophobic steroid substrates across cell membrane is a critical factor during microbial bioconversion. To increase substrate intake, the feasibility of some organic solvents and emulsifiers as substrate carrier on the bioconversion of 6-methylene androstenedione to exemestane was assessed.Methods: Androstenedione, a commonly available steroid precursor, was chemically converted 6-methylene androstenedione. The time course of exemestane accumulation was estimated after addition of 6-methylene androstenedione dissolved in some organic solvents or dispersed with emulsifiers by growing and immobilized cells of Arthrobacter simplex NCIM 2449 in shake flask cultures. Results: The use of substrate carriers for addition of 6-methylene androstenedione enhanced the bioconversion several folds. With growing bacterium in triplicate flasks, a peak mol % bioconversion recorded was- ethanol (67.25, 72 h); soybean oil + tween 80 (50.37, 48 h); acetone (38.84, 48 h); soybean oil (38.36, 48 h); lecithin (32.73, 48 h), methanol (32.71, 48 h) and tween 80 (10.37, 48 h). As compared to the growing cells, the bioconversion with Ca-alginate immobilized cells was delayed and peak mol % bioconversion was recorded as ethanol (60.78, 120 h); soybean oil + tween 80 (42.98, 120 h); methanol (40.50, 72 h); soybean oil (38.36, 48 h); acetone (31.18, 72h ) and lecithin (33.67, 120 h); tween 80 (13.87, 120 h).Conclusion: The use of substrate carriers for addition of 6-methylene androstenedione increased the permeability of substrate and may be used to increase the yield of exemestane and reduce incubation time.

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Steroids derived from fusidic acid. Part 3. Formation of a 9β-steroid from a Δ9,111-steroid precursor. X-Ray crystal structure of 3α-acetoxy-4α,8α,14β-trimethyl-18-nor-5α,9β,13β-androstan-17-one

Journal of the Chemical Society Perkin Transactions 1 ◽

10.1039/p19790001447 ◽

1979 ◽

pp. 1447-1450 ◽

Cited By ~ 4

Author(s):

William S. Murphy ◽

David Cocker ◽

George Ferguson ◽

Masood Khan

Keyword(s):

Crystal Structure ◽

Fusidic Acid ◽

X Ray ◽

Steroid Precursor

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Adrenarche Results from Development of a 3β-Hydroxysteroid Dehydrogenase-Deficient Adrenal Reticularis1

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jcem.83.10.5070 ◽

1998 ◽

Vol 83 (10) ◽

pp. 3695-3701 ◽

Cited By ~ 1

Author(s):

Jennifer S. Gell ◽

Bruce R. Carr ◽

Hironobu Sasano ◽

Baron Atkins ◽

Linda Margraf ◽

...

Keyword(s):

Adrenal Glands ◽

Dehydroepiandrosterone Sulfate ◽

Hydroxysteroid Dehydrogenase ◽

Immunohistochemical Localization ◽

The Other ◽

Age Group ◽

Other Hand ◽

Significant Difference ◽

Steroid Precursor

Adrenarche is the increased adrenal production of dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) that occurs during the prepubertal period. To date, the exact mechanism initiating adrenarche is unknown, although many factors have been postulated. In the present study, we examined the hypothesis that alterations in intra-adrenal expression of 3β-hydroxysteroid dehydrogenase (3βHSD) or 21-hydroxylase (CYP21) within the inner reticularis zone leads to the increased production of 19-carbon (C19) steroids. After conversion of cholesterol to pregnenolone, 17α-hydroxylase/17,20-lyase (CYP17) can metabolize pregnenolone through to DHEA. The enzyme 3βHSD competes for substrate with CYP17 and effectively removes steroid precursor from the pathway leading to DHEA. On the other hand, deficiency in CYP21 expression is known to cause excessive production of adrenal C19 steroids, suggesting that CYP21 could play a role in adrenarche. Thus, a decrease in 3βHSD or CYP21 expression would allow substrate to flow toward the synthesis of DHEA. To determine whether adrenarche results from a decreased expression of 3βHSD or CYP21 in the reticularis, immunohistochemical localization of 3βHSD and CYP21 was performed, and staining intensities compared using adrenal glands from children ages 4 months to 4 yr (n = 12), ages 5–7 yr (n = 9), ages 8–13 yr (n = 9), and adults ages 25–56 yr (n = 8). There were no differences in the zonal expression of CYP21. No difference in 3βHSD staining was observed between the glomerulosa and fasciculata from any age group. However, children age 8 yr and older show a significant decrease in 3βHSD expression in reticularis as compared with the fasciculata. No significant difference was noted for 3βHSD levels between the fasciculata and reticularis for children age 7 yr or younger. The level of 3βHSD expression in the reticularis continued to decrease in the adult adrenals examined. These findings suggest that as children mature there is a decreased level of 3βHSD in the adrenal reticularis that may contribute to the increased production of DHEA and DHEAS seen during adrenarche.

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Regulation of human fetal testicular secretion of testosterone: Low-density lipoprotein-cholesterol and cholesterol synthesized de novo as steroid precursor

American Journal of Obstetrics and Gynecology ◽

10.1016/0002-9378(83)90743-3 ◽

1983 ◽

Vol 146 (3) ◽

pp. 241-247 ◽

Cited By ~ 23

Author(s):

Bruce R. Carr ◽

C.Richard Parker ◽

Masao Ohashi ◽

Paul C. MacDonald ◽

Evan R. Simpson

Keyword(s):

De Novo ◽

Low Density Lipoprotein ◽

Density Lipoprotein ◽

Lipoprotein Cholesterol ◽

Low Density ◽

Low Density Lipoprotein Cholesterol ◽

Steroid Precursor

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1-14C-acetyl-coenzyme A as steroid precursor in the monkey adrenal in vitro

Cellular and Molecular Life Sciences ◽

10.1007/bf01899920 ◽

1969 ◽

Vol 25 (4) ◽

pp. 364-365

Author(s):

P. Knapstein ◽

J. C. Touchstone

Keyword(s):

Coenzyme A ◽

Acetyl Coenzyme A ◽

Acetyl Coenzyme ◽

Steroid Precursor

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SAT-744 Spiral Steroid Lactones Are Synthesized by Condensation of a Steroid Precursor with Coenzyme a Derivatives

Journal of the Endocrine Society ◽

10.1210/jendso/bvaa046.123 ◽

2020 ◽

Vol 4 (Supplement_1) ◽

Author(s):

Fred I Chasalow

Keyword(s):

Ion Trap ◽

Structural Features ◽

Side Chain ◽

Chemical Formula ◽

Serum Samples ◽

Long Chain Fatty Acid ◽

Fragment Ions ◽

Chain Cleavage ◽

Endogenous Ouabain ◽

Steroid Precursor

Abstract Background: Szent-Gyorgyi proposed that digoxin wasn’t really drug but was a substitute for an endogenous cardiotonic steroid (ECS). Endogenous ouabain and marinobufagenin have been proposed as ECS. Hypothesis: Ionotropin, our first candidate for the ECS, is unique among steroids because it is the phosphocholine ester of a steroid with 23 carbon atoms. Logically, either there must be a novel mechanism for adding carbon atoms to a pregnenolone-like precursor or a novel mechanism for side-chain cleavage from a cholesterol-like precursor. Experimental design: Serum samples were extracted with acetonitrile, filtered and analyzed by MS-N on an LTQ-XL ion trap mass spectrometer. The instrument permits multiple rounds of fragmentation and identification of the parent ion and each fragment ion. This process permitted recognition of ions that were phosphocholine esters and of the mass of the steroid fragments. The chemical formula of each steroid fragment was determined by trial and error analysis. Although not every mass ion has a unique chemical formula, in fact, each of the steroid ions had a unique formula. Possible isomers were resolved by consideration of knowledge of steroid biosynthetic pathways. Major results: In brief, human serum samples had steroid fragment ions consistent with 23 (354 Da) and 25 (398 Da) carbon atoms. This provides an additional constraint as the synthetic mechanism must account for both products. These mass ions were consistent with condensation of either acetyl-CoA or acetoacetyl-CoA with the phosphocholine ester of pregna-5,7-diene-3β,17α-diol-20-one. After condensation, the steroid adduct would be dehydrated and cyclized to form the corresponding spiral steroid phosphocholine ester. This pathway is similar to the mechanism of addition of 2 carbon fragments to a long chain fatty acid. This is the first explanation for the biosynthesis of endogenous mammalian ECS. Spiral lactones would be expected to cross react with many antibodies specific for digoxin, ouabain or marinobufagenin. Either one of the spiral lactones would satisfy Szent-Gyorgyi’s suggestion as the endogenous digoxin-like material. Conclusions: In summary, we have isolated 2 spiral steroid lactones from mammals and identified the mechanism of their biosynthesis. We propose, as the spiral steroids share structural features with the spironolactone class of potassium sparing diuretics, that they also share functions. Nicholls proposed that a candidate for ECS should not be accepted without [a] isolation, [b] precursors, and [c] a biosynthetic path. As there has been no satisfaction of these requirements for ouabain or marinobufagenin, their existence as ECS in mammals needs to be reconsidered.

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