Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Pregnenes”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed1994

Reduction of predator odor-induced anxiety in mice by the neurosteroid 3 alpha-hydroxy-4-pregnen-20-one (3 alpha HP).

The effects of the centrally produced allylic neurosteroid, 3 alpha-hydroxy-4-pregnen-20-one (3 alpha HP), on the responses of male mice to an aversive, anxiety-inducing, predator (cat) odor were examined in an odor preference test. Control untreated mice displayed an anxiogenic response to the cat odor, spending a minimal amount of time in a Y-maze in the vicinity of the cat odor. Intracerebroventricular (i.c.v.) administrations of 3 alpha HP had an anxiolytic action, resulting in significant dose-related (0.01-1.0 micrograms) increases in the amount of time spent in the proximity of the cat odor. These anxiolytic effects of 3 alpha HP were stereospecific, with the stereoisomer, 3 beta-hydroxy-4-pregnen-20-one (3 beta HP) having no significant effects on odor preferences. The analgesic, morphine, also had no significant effects on the response to cat odor indicating that the anxiolytic actions of 3 alpha HP were unlikely to be related to any analgesic effects. The effects of 3 alpha HP were significantly reduced by peripheral administrations of the GABAA antagonists, bicuculline and picrotoxin, but were unaffected by either the benzodiazepine antagonist, Ro 15-1788, or the opiate antagonist, naloxone. These results indicate that the allylic neurosteroid 3 alpha HP has anxiolytic actions involving interactions with the GABAA receptor.

20-alpha-Dihydroprogesterone↗
PubMed1987

A simple, rapid, and precise direct radioimmunoassay method for 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one in salmon plasma.

This report describes a radioimmunoassay method for 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-diOHP) in the blood plasma of Atlantic salmon (Salmo salar). 3H-labeled 17 alpha,20 beta-diOHP was synthesized from 17 alpha-[3H]hydroxy-4-pregnen-3-one (17 alpha-OHP) by enzymatic reduction of the C-20 oxo group and the simultaneous oxidation of coenzyme-reduced nicotinamide adenine dinucleotide. Antiserum to 17 alpha,20 beta-diOHP-3-CMO-BSA exhibited high specificity: all steroids tested against the antiserum gave less than 1% cross-reactivity at 50% displacement. Crude dichloromethane extracts of small volumes (50 microliters or less) of plasma can be assayed directly without prior purification. The working range is 5 to 300 pg. Interassay and intraassay coefficients of variation were less than 10%. Various parallelism tests showed high accuracy and sensitivity. The assay is simple and rapid and at least 75 samples can be easily assayed in duplicate by two analysts in 1 day.

Animals↗
PubMed1990

Characterization of membrane receptor activity for 17 alpha, 20 beta, 21-trihydroxy-4-pregnen-3-one in ovaries of spotted seatrout (Cynoscion nebulosus).

The proposed maturation-inducing substance (MIS) of spotted seatrout (Cynoscion nebulosus) is 17 alpha, 20 beta, 21-trihydroxy-4-pregnen-3-one (20 beta-S). In this study, we characterized the binding of radioactive 20 beta-S to plasma membranes from the ovaries of spotted seatrout. Bound 20 beta-S was isolated by filtration of membrane suspensions and quantified by measurement of the radioactivity content of the filters. The saturable component of 20 beta-S binding reached equilibrium within 5 min at 0 degree, showed linearity with membrane concentration, and was pH dependent (optimum, 7.5-7.8). Scatchard analyses suggested a single class of high-affinity (KD, 10(-9) M), low-capacity (10(-13)-10(-12) mol/g ovary) binding sites for 20 beta-S. High levels of saturable binding were found in membrane preparations from the ovary, testis, and liver, but not from the gills. 17 alpha, 20 beta-Dihydroxy-4-pregnen-3-one (17 alpha, 20 beta-P) showed relatively little affinity for the 20 beta-S binding site. However, this steroid was converted to a compound immunologically and chromatographically similar to 20 beta-S by intact ovarian follicles, a finding which may explain its previously reported high potency in an in vitro oocyte maturation bioassay. Conversely, although reportedly a weak inducer of oocyte maturation, progesterone readily displaced 20 beta-S from its binding site. Thus, progesterone appears to be a relatively inactive ligand with high affinity for the 20 beta-S receptor. The concentration of 20 beta-S binding sites in ovaries was significantly higher during final oocyte maturation (germinal vesicle migration) than at earlier stages of development. These results strongly suggest that the 20 beta-S binding activity characterized in our study represents authentic MIS receptors. A distinct, soluble binding site for 17 alpha, 20 beta-P was also identified in seatrout ovaries, but its biological function remains unclear. A hypothesis is presented for the significance of this 17 alpha,20 beta-P binding site.

17-Hydroxycorticosteroids↗
PubMed1990

Identification of, and development of radioimmunoassays for 17 alpha, 21-dihydroxy-4-pregnene-3,20-dione and 3 alpha,17 alpha, 21-trihydroxy-5 beta-pregnan-20-one in the ovaries of mature plaice (Pleuronectes platessa).

Ovaries from a female plaice (Pleuronectes platessa) that had been injected with human chorionic gonadotrophin were incubated in vitro with 17 alpha-hydroxy[1,2,6,7-3H]progesterone. The major steroids produced by the ovaries were tentatively identified as 17 alpha,21-dihydroxy-4-pregnene-3,20di-one (11-deoxycortisol; 17,21-P), 17 alpha,21-dihydroxy-5 beta-pregnane-3,20-dione (3 alpha, 17,21-P-5 beta). A high proportion of these steroids was found in a conjugated form (sulphates or glucuronides). Radioimmunoassays were developed for 11-deoxycortisol and for 3 alpha,17,21-P-5 beta and were applied to fractions of mature male and female plaice plasmas and plaice ovarian incubates that had been separated on thin-layer chromatography. The presence of all three steroids, in vivo and in vitro, was confirmed. Particularly high amounts of conjugated 3 alpha,17,21-P-5 beta were found in the plasma of mature females (200-400 ng ml-1). The 3 alpha,17,21-P-5 beta radioimmunoassay also identified 3 alpha,17 alpha-dihydroxy-5 beta-pregnane-20-dione in all three fluids, despite the fact that this steroid was not among the radioactive incubation products of the ovary. These findings are compared with those from another flatfish, the dab (Limanda limanda), where the major gonadal steroids have been shown to be 17 alpha,20 alpha-dihydroxy-4-pregnen-3-one and its 5 beta-pregnane (3-keto and 3 beta-hydroxyl) metabolites.

17-Hydroxycorticosteroids↗
PubMed1991

Biosynthesis of 17 alpha,20 beta-dihydroxy-4-pregnen-3-one in the ovaries of grey mullet (Mugil cephalus) during induced ovulation by carp pituitary homogenates and an LHRH analogue.

Three female mullets received a priming injection of carp pituitary homogenate followed by a resolving injection of an LHRH analogue 24 hr later. Ovarian biopsies were obtained just prior to the first injection (phase I), 24 hr after the first injection (i.e., immediately before the second injection, phase II), and 8 hr after the second injection (phase III). Two fish (Nos. 1 and 3) spawned approximately 12 hr after the second injection. Serum levels of testosterone increased to some extent during phase II in all of the fish. Testosterone levels decreased abruptly during phase III in both fish Nos. 1 and 3. In contrast the concentration of 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-diOHprog) was undetectable in phases I and II, and increased dramatically during phase III in the same fish. In fish No. 2, which did not spawn, neither the decrease of testosterone nor the increase of 17 alpha,20 beta-diOHprog was observed. Ovarian tissues of all the fish were pooled in each phase and incubated with 14C-labeled progesterone or 17 alpha-hydroxyprogesterone to investigate steroid metabolism. During phases I and II progesterone was converted to 17 alpha-hydroxyprogesterone, androstenedione, and testosterone. During phase III, production of these steroids decreased drastically, and in turn, synthesis of 20 beta-hydroxy-4-pregnen-3-one and 17 alpha,20 beta-diOHprog was induced. Using 17 alpha-hydroxyprogesterone as a substrate, androstenedione and testosterone were produced during phases I and II, whereas they decreased considerably during phase III. This was followed by the production of 17 alpha,20 beta-diOHprog as the major metabolite.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1981

Prostatic cancer. I. 6-Methylene-4-pregnen-3-ones as irreversible inhibitors of rat prostatic delta 4-3 ketosteroid 5 alpha-reductase.

Some derivatives of 6-methylene-4-pregnen-3-one were studied as inhibitors of delta 4-3-ketosteroid 5 alpha-reductase. Maximum inhibitory activity was shown by 17-acetoxy-6-methylene-4-pregnene-3,20-dione (AMPD). Irreversible inactivation was observed following preincubation of the enzyme with NADPH and AMPD. This inactivation was found to occur only in the presence of NADPH. As such enzyme inactivation was not due to the formation of a more inhibitory metabolic product, or to the formation of superoxide via a cytochrome P-450/NADPH pathway, it seemed likely that the observed inactivation was derived from an irreversible combination of the enzyme with AMPD. That this was probably the case was established by kinetic studies which revealed a pattern compatible with a kcat type of mechanism.

5-alpha Reductase Inhibitors↗
PubMed1985

Synthesis of the allylic gonadal steroids, 3 alpha-hydroxy-4-pregnen-20-one and 3 alpha-hydroxy-4-androsten-17-one, and of 3 alpha-hydroxy-5 alpha-pregnan-20-one.

A method for the convenient synthesis of the recently isolated allylic gonadal steroids, 3 alpha-hydroxy-4-pregnen-20-one (3 alpha-dihydroprogesterone; 3 alpha-DHP) and 3 alpha-hydroxy-4-androsten-17-one (3 alpha-HA), was developed using 4-pregnene-3,20-dione (progesterone) and 4-androstene-3,17-dione as substrates and potassium trisiamylborohydride (KS-Selectride) as reducing agent. Similar reactions were also used for the reduction of 5 alpha-pregnane-3,20-dione to 3 alpha-hydroxy-5 alpha-pregnan-20-one (3 alpha-HP). The yields were about 15%, 50%, and greater than 90% for 3 alpha-DHP, 3 alpha-HA and 3 alpha-HP, respectively. Structures of the products, including the 3 beta-isomers and the 17 alpha-epimer, formed in these reactions were determined by NMR and mass spectroscopic methods.

Androstenedione↗
PubMedDate not supplied

Identification of 17 alpha,20 beta,21-trihydroxy-4-pregnen-3-one as the major ovarian steroid produced by the teleost Micropogonias undulatus during final oocyte maturation.

This study describes the identification of 17 alpha,20 beta, 21-trihydroxy-4-pregnen-3-one (20 beta-dihydro-11-deoxycortisol, 20 beta-S) as a major steroid product of the ovary of Atlantic croaker (Micropogonias undulatus) incubated in vitro. This is the first report which describes 17 alpha,20 beta,21-trihydroxy-4-pregnen-3-one as a major product of teleost steroidogenic tissue. The steroid was identified by a variety of methods, including HPLC, TLC, GC-MS, UV absorbance, and reactions with specific enzymes. Full grown oocytes, prior to final oocyte maturation (FOM), accumulated only small amounts of 20 beta-S. However, a substantial increase in 20 beta-S production occurred at the time of FOM. These results suggest that 20 beta-S is a maturational steroid in this species.

17-Hydroxycorticosteroids↗
PubMed1992

Identification of 2 alpha-hydroxy-4-pregnene-3,20-dione in human pregnancy urine.

2 alpha-Hydroxyprogesterone (2 alpha-hydroxy-4-pregnene-3,20-dione) was identified in human late pregnancy urine by liquid-gel chromatography, GLC and GC-MS. In addition, the following 2-hydroxylated C21 steroids were found and identified as 2 zeta-hydroxy-5 zeta-pregnane-3,20-dione, 2 zeta,20 zeta-dihydroxy-4-pregnen-3-one, 2 alpha,3 alpha-dihydroxy-5 alpha- (and 5 beta)-pregnan-20-one, two isomers of pregnane-2,3,20-triol and 2 zeta,3 zeta,16 zeta-trihydroxy-5 zeta-pregnan-20-one.

Chromatography, Gel↗
PubMed1992

4-pregnene-3-one-20 beta-carboxaldehyde: a potent inhibitor of 17 alpha-hydroxylase/C17,20-lyase and of 5 alpha-reductase.

The pregnene derivative, 4-pregnene-3-one-20 beta-carboxaldehyde (22-A) was evaluated as an inhibitor of 17 alpha-hydroxylase/C17,20-lyase in rat testicular microsomes and of 5 alpha-reductase in human prostatic homogenates. The effect of the compound in vivo was studied in adult male rats. The 22-A demonstrated potent and competitive inhibition of 17 alpha-hydroxylase and C17,20-lyase with Ki values 8.48 and 0.41 microM, respectively, significantly below the Km values for these two enzymes (33.75 and 4.55 microM). This compound also showed potent inhibition of 5 alpha-reductase with a Ki value of 15.6 nM (Km for this enzyme is 50 nM). By comparison, ketoconazole, a currently studied 17 alpha-hydroxylase/C17,20-lyase inhibitor for the treatment of prostatic cancer, showed less potent inhibition of 17 alpha-hydroxylase (Ki 39.5 microM) and C17,20-lyase (Ki 3.6 microM) and did not inhibit 5 alpha-reductase. Progesterone which has been reported to inhibit the 17 alpha-hydroxylase/C17,20-lyase, did not significantly reduce the production of testosterone by rat testes in vitro in comparison to controls, while the same concentration of 22-A demonstrated a 42% reduction of testosterone biosynthesis. When the adult male rats were injected s.c. with 22-A at 50 mg/day/kg for a 2 week period, the testosterone concentrations in the rat sera were significantly lower than control values (P less than 0.05), whereas serum corticosterone levels did not change. These results suggest that 22-A is a selective potent inhibitor for 17 alpha-hydroxylase and C17,20-lyase, but is more potent for the C17,20-lyase. The compound also inhibits 5 alpha-reductase, and therefore may reduce biosynthesis of testosterone and dihydrotestosterone effectively. Thus, 22-A may be useful in the treatment of problems associated with the androgen excess and prostatic cancer.

5-alpha Reductase Inhibitors↗
PubMed2004

Evidence that 4-pregnen-17,20beta,21-triol-3-one functions as a maturation-inducing hormone and pheromonal precursor in the percid fish, Gymnocephalus cernuus.

Behavioral, biochemical, and electrophysiological studies suggest that the trihydroxylated progestin steroid, 4-pregnen-17,20beta,21-triol-3-one (20beta-S) stimulates oocyte maturation and pheromone release in the Eurasian ruffe, a freshwater percid fish. Behavioral observations found that female ruffe undergoing oocyte maturation (OM) release a pheromonal cue that stimulates swimming activity and social interactions among conspecific males. Neither vitellogenic nor ovulated females released the cue. Pheromone production was directly associated with elevated plasma levels of 20beta-S in maturing female ruffe which in vitro incubation suggested to be a possible maturation-inducing hormone (MIH) in this species along with 4-pregnen-17,20beta-diol-3-one (17,20betaP). However, neither of these steroids appear to be the pheromone because electrophysiological and behavioral studies found them to lack olfactory (EOG) and behavioral activity. Instead, studies of the odor of steroid-injected fish suggest the pheromone is a metabolite of 20beta-S. In particular, inter-peritoneal injection of 20beta-S (but not 17,20betaP) consistently induced release of a urinary cue with strong behavioral activity. The pheromone may be a highly polar and novel metabolite because it could not be extracted using octadecylsilane resin (C18) which has proven effective for other teleost hormonal pheromones.

Animals↗
PubMed2004

Identification of 17,20beta,21-trihydroxy-4-pregnen-3-one as an oocyte maturation-inducing steroid in black porgy, Acanthopagrus schlegeli.

The identity of the maturation-inducing steroid (MIS) in black porgy, Acanthopagrus schlegeli, a marine protandrous teleost, is unknown. Previous studies demonstrated that two teleost MISs, the progestins 17,20beta,21-trihydroxy-4-pregnen-3-one (20beta-S) and 17,20beta-dihydroxy-4-pregnen-3-one (DHP) can induce maturation of black porgy oocytes in vitro. The purpose of the present study was to identify the major progestin produced during oocyte maturation (OM) in black porgy and investigate whether its secretion increases during this process. Females were injected twice with a LHRH analog to induce OM. Ovarian follicles undergoing OM were incubated in vitro with tritiated [3H]pregnenolone precursor and the tritiated products were extracted, purified, and identified by HPLC, TLC, acetylation, and recrystallization. Significant amounts of tritiated products were biosynthesized from [3H]pregnenolone that co-migrated with 20beta-S but not with DHP on HPLC and TLC. Similar TLC profiles were obtained with the tritiated products isolated from the HPLC/TLC 20beta-S fraction and standard 20beta-S after the acetylation reaction. The identity of the tritiated products as 20beta-S was confirmed by recrystallization. 20beta-S had a slightly higher potency than DHP in the inducing in vitro final oocyte maturation. Plasma 20beta-S concentrations increased significantly during the oocyte maturation after injection with a LHRH analog. The present data suggest that 20beta-S is the MIS in black porgy.

Acetylation↗
PubMed1989

Selective suppression of follicle-stimulating hormone secretion in anterior pituitary cells by the gonadal steroid 3 alpha-hydroxy-4-pregnen-20-one.

The effect of 3 alpha-hydroxy-4-pregnen-20-one (3HP), a Sertoli cell steroid, on the secretion of gonadotropins from rat anterior pituitary cells in culture was examined and subsequently compared with the action of other gonadal steroids and steroids structurally related to 3HP. Pituitary cells from randomly cycling, sexually mature female rats were isolated and maintained in culture 72 h before use. On the day of treatment, medium was changed, steroids (10(-16)-10(-4) M) and/or LHRH (10(-8) M) were added, and cells were allowed to incubate for a further 24 h. Medium was then examined for gonadotropin content by RIA. 3HP treatment of anterior pituitary cells resulted in a significant reduction of both basal and LHRH-induced FSH secretion, while LH secretion was unaffected. The lowest effective dose of 3HP (10(-16) M) significantly decreased basal FSH secretion to 65.6% of control levels. The lowest effective dose of 3HP that significantly inhibited (by 31%) LHRH-induced FSH secretion was 10(-14) M 3HP. Maximum suppression by 3HP of basal FSH secretion occurred between 10(-10)-10(-8) M, and maximum suppression of LHRH-induced secretion occurred at 10(-12) M. None of the other gonadal steroids tested (progesterone, testosterone, 5 alpha-dihydrotestosterone, 17 beta-estradiol, 20 alpha-hydroxy-4-pregnen-3-one, and 5 alpha-pregnane-3,20-dione) had a similar selective effect on FSH secretion; progesterone, testosterone, and 17 beta-estradiol actually resulted in increased FSH release, and 5 alpha-pregnane-3,20-dione resulted in significant increase in basal LH. A number of metabolites and structural variations of 3HP were examined in this in vitro system at concentrations of 10(-12)-10(-6) M, and none exhibited a similar selective FSH-suppressing activity as 3HP. The data suggest that the selective FSH-suppressing effect of 3HP seen previously in vivo and here in vitro is due to 3HP itself and not the result of a metabolite of this molecule.

20-alpha-Dihydroprogesterone↗
PubMed1987

[Studies on 17 alpha, 20 alpha-dihydroxy-4-pregnen-3-one in non-pregnant and pregnant women by a new radioimmunoassay system].

17 alpha, 20 alpha-dihydroxy-4-pregnen-3-one (17 alpha, 20 alpha-P) is reportedly a hyper-tensinogenic substance in a model of ACTH induced hypertension in sheep (Scoggins et al). This steroid has not previously been measured in Japan. We have developed a new radioimmunoassay (RIA) system for 17 alpha, 20 alpha-P, and measured this steroid in peripheral blood samples from non-pregnant and pregnant women. In this clinical investigation concentrations of 17 alpha-hydroxyprogesterone (17 alpha-OHP) and progesterone (P) were also measured in the same clinical samples. Specific anti-serum against 17 alpha, 20 alpha-P-3-carboxymethyloxime-BSA was generated in rabbits. Cross-reactions with 5-pregnen-3 beta, 17 alpha 20 alpha-triol (17 alpha, 20 alpha-P5) and 17 alpha-OHP were 42 and 2.4%, respectively. Other steroids showed cross-reactivity of less than 1%. As an internal standard dexamethasone (500 ng/100 microliter) was added to the samples which were extracted twice with 6 volumes of dichloromethane. Separation of the plasma extract was performed by high performance liquid chromatography (HPLC) with the ODS column in the solvent system, acetonitrile:water = 55:45. Eluates of the 17 alpha, 20 alpha-P and 17 alpha-OHP fractions were collected separately and the solvent was evaporated in vacuo. RIA was carried out on each extract with specific anti-sera. RIA of P was performed independently using the anti-P-3-CMO-BSA antiserum; 0.1 ml of serum was extracted with n-hexane and subjected to RIA without chromatography. The coefficient of variation for intra- and interassay (n = 10) were 8.5 and 11.7% for 17 alpha, 20 alpha-P; 7.2 and 12.1% for 17-OHP and 10.5 and 14.0% for P, respectively. The recovery rates of 17 alpha, 20 alpha-P, 17 alpha-OHP and P were 95 +/- 1.5, 93.2 +/- 3.5 and 97.5 +/- 4.2%, respectively. With the use of this method, 17 alpha, 20 alpha-P was measured in the blood samples from the menstrual cycle and normal pregnancy. The mean serum 17 alpha, 20 alpha-P concentrations +/- SD in the follicular, ovulatory and luteal phases, and in the first, second and third trimesters were; 76 +/- 6.0, 100 +/- 31, 101 +/- 6.4, 226 +/- 80, 151 +/- 48 and 367 +/- 99 pg/ml, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1989

Conjugates of ovarian steroids, including 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (maturation-inducing steroid), accumulate in the urine of a marine teleost (plaice; Pleuronectes platessa).

Free and conjugated 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta-P), 17 alpha,21-dihydroxy-4-pregnene-3,20-dione (11-deoxycortisol) and 3 alpha,17 alpha,21-trihydroxy-5 beta-pregnan-20-one (3 alpha,17,21-P-5 beta) were measured by radioimmunoassay in matching blood plasma and urine samples from plaice (Pleuronectes platessa) females at several ovarian maturity stages: post-vitellogenesis (IV), final oocyte maturation (V), and ovulation (VI). Free steroids were generally low in all samples. Conjugated steroids were up to 2 orders of magnitude higher in urine than in plasma samples. Conjugated 17,20 beta-P was higher in stage V than in stage IV or VI females. Conjugated 11-deoxycortisol was higher in stage IV and V females. Conjugated 3 alpha,17,21-P-5 beta was higher in stage V and VI females. These results support earlier studies which indicated that 17,20 beta-P was the most likely maturation-inducing steroid (MIS) in plaice, and that the urine might be a vehicle for steroid pheromones synthesized by the gonads.

Animals↗
PubMedDate not supplied

[Determination of progesterone and delta 4-pregnen-20 alpha-ol-3-one contents in ovaries with two-dimensional thin-layer chromatography and spectrofluorimetry].

The method is developed for quantitative determination of progesterone and delta4-pregnen-20alpha-ol-3-one in ovaries. It includes treatment of the gland homogenate with NaOH, ethylacetate extraction, two-dimensional thin-layer chromatography on silicaged plate Silufol UV254 in benzol-ethylacetate (80:20) and chlorophorm-ethanol (98:2) and the subsequent spectrofluorimetry. For identification of the isolated steroids their chromatographical motility, light absorption, color reactions and fluorescence spectra were studied. The contents of progesterone and delta4-pregnen-20alpha-ol-3 one in the rat ovaries were determined by this method.

Animals↗
PubMed1982

Acyl migration in the Reformatsky reaction of 21-acyloxy-5-pregnen-20-one derivatives with ethyl bromoacetate.

Reformatsky reaction of 3beta, 21-diacyloxy-and 3beta-methoxy-21-acyloxy-5-pregnen-20-one with ethyl bromoacetate yields, through an intramolecular 1,2-acyl migration, 38, 20 XI-acyloxy-14alpha-card-5-enolides were converted into the respective 20 XI-hydroxy-14alpha-card-5-enolides and the 14 alpha-carda-5,20(22)-dienolides. Experimental support to the proposed intramolecular 1,2-acyl migration is provided by the use of labelled compounds.

Acetates↗