QUANTITATIVE ASSESSMENT OF THE DE NOVO STEROL AND STEROID SYNTHESIS IN THE HUMAN FOETO-PLACENTAL UNIT

1971 ◽  
Vol 66 (4) ◽  
pp. 666-678 ◽  
Author(s):  
D. F. Archer ◽  
R. S. Mathur ◽  
N. Wiqvist ◽  
E. Diczfalusy
Keyword(s):  
Sodium Acetate ◽  
Quantitative Assessment ◽  
De Novo ◽  
Isolation Procedure ◽  
Predominant Formation ◽  
Human Foetus ◽  
Steroid Synthesis ◽  
Internal Standards ◽  
Carbon 14 ◽  
Hydroxy Progesterone

ABSTRACT The quantitative significance of the de novo synthesis of Δ5- and Δ4-steroids was assessed in the midgestation human foetus. Two midgestation foetuses and two complete foeto-placental units were perfused at 36°C for 120 minutes with 3.0 and 6.0 mCi of [14C] sodium acetate, respectively, and radiochemically homogeneous carbon-14 labelled steroids were isolated from the adrenals, livers and perfusates. Losses throughout the isolation procedure were monitored in all tissues of all experiments by the recovery of tritium labelled internal standards. In the four experiments, a total of 18.0 mCi of [14C] sodium acetate was perfused and a total of 0.17 μCi of pregnenolone, 2.65 μCi of pregnenolone sulphate, 1.07 μCi of dehydroepiandrosterone and 8.64 μCi of dehydroepiandrosterone sulphate were isolated. A total of 12.53 μCi were isolated in the form of these four compounds; 10.13 μCi of this was present in the perfusates. In all, 0.07% of the administered [14C]-sodium acetate was converted to the four Δ5-steroids studied and 0.048% to dehydroepiandrosterone sulphate. Progesterone was isolated from the perfusates and liver extracts, and 17α-hydroxy-progesterone, androstenedione and testosterone from the perfusates. In the four experiments, a total of 0.045 μCi of carbon-14 labelled Δ4-steroids were isolated, predominantly from the perfusates. In all, less than 0.0003% of the perfused [14C] sodium acetate was converted to Δ4-steroids. Thus, almost 300 times more Δ5- than Δ4-steroids were formed. It is concluded that the extensive de novo steroidogenetic processes taking place in the midgestation human foetus lead to the predominant formation of Δ5-steroid sulphates.

QUANTITATIVE ASSESSMENT OF THE DE NOVO STEROL AND STEROID SYNTHESIS IN THE HUMAN FOETO-PLACENTAL UNIT.

1970 ◽  
Vol 65 (4) ◽  
pp. 663-674 ◽  
Author(s):  
R. S. Mathur ◽  
D. F. Archer ◽  
N. Wiqvist ◽  
E. Diczfalusy
Keyword(s):  
Sodium Acetate ◽  
Quantitative Assessment ◽  
Cholesterol Synthesis ◽  
De Novo ◽  
Internal Standard ◽  
The Other ◽  
Radioactive Material ◽  
Human Foetus ◽  
Steroid Synthesis ◽  
Average Quantity

ABSTRACT In order to assess the quantitative significance of the de novo cholesterol synthesis in the foeto-placental unit at midgestation, two midgestation foetuses and two complete foeto-placental units were perfused with [14C]-sodium acetate immediately following their removal at laparotomy. The perfusions were carried out at 36°C for 120 min administering 3.0 and 6.0 mCi of [14C] sodium acetate, respectively. The amount of [14C]-cholesterol formed was estimated on the basis of the recovery of [7α-3H]-cholesterol internal standard present in the radiochemically homogeneous cholesterol isolated from the various tissues. The cholesterol isolated from the placentas was devoid of any [14C] label. On the other hand, [14C] cholesterol was isolated from all perfusates, as well as from all foetal tissues studied, including the adrenals, livers, testicles, brains and residual foetal tissues. The average quantity of radiochemically homogeneous [14C] cholesterol formed by the four foetuses corresponded to 0.68% of the radioactive material perfused: 0.45% was isolated from the liver, 0.13% from the adrenals, 0.01% from the testicles and 0.08% from the perfusates. Cholesterol sulphate was also isolated from the extracts of adrenals, livers and perfusates. The quantity of [14C] cholesterol sulphate formed was much less than that of [14C] cholesterol; following correction for procedural losses, the total amount of [14C] cholesterol sulphate isolated did not exceed 0.01% of the perfused material. It is concluded that the midgestation human foetus synthesizes large quantities of cholesterol, utilizing small molecular material such as sodium acetate as a precursor and that part of the cholesterol synthesized by the foetus is secreted to the placenta.

ACETATE AND CHOLESTEROL METABOLISM IN THE HUMAN FOETO-PLACENTAL UNIT AT MIDGESTATION

1970 ◽  
Vol 63 (1) ◽  
pp. 119-133 ◽  
Author(s):  
G. Telegdy ◽  
J. W. Weeks ◽  
D. F. Archer ◽  
N. Wiqvist ◽  
E. Diczfalusy
Keyword(s):  
Sodium Acetate ◽  
De Novo ◽  
Cholesterol Metabolism ◽  
Human Foetus ◽  
Homogeneous Form ◽  
Per Se ◽  
Hydroxy Progesterone

ABSTRACT Two complete foeto-placental units were perfused at midgestation with 5.0 mCi of uniformly labelled 14C-sodium acetate plus 5.0 mCi of cholesterol-7α-3H and two isolated foetuses were perfused with 2.5 mCi of 14C-labelled sodium acetate plus 2.5 mCi of cholesterol-7α-3H. The perfusions were carried out at 35–36°C for 90 min. The foetal adrenals, livers, testes and perfusates were analyzed and various labelled steroids were isolated in a radiochemically homogeneous form. Major quantities of 14C- and 3H-labelled pregnenolone (3β-hydroxy-pregn-5-en-20-one) and dehydroepiandrosterone (3β-hydroxy-androst-5-en-17-one) were isolated from the foetal perfusates, livers and adrenals. Minor amounts of 14C- and 3H-labelled progesterone (pregn-4-ene-3,20-dione) were isolated from the perfusates and adrenals, and 17α-hydroxy-progesterone (17α-hydroxy-pregn-4-ene-3,20-dione) and androstenedione (androst-4-ene-3,17-dione) from the perfusates. Smaller amounts of exclusively 14C-labelled androstenedione were isolated also from the adrenals. No labelled progesterone, androstenedione or testosterone (17β-hydroxy-androst-4-en-3-one) was detected in the testes. Attempts to isolate 20α-dihydroprogesterone (20α-hydroxy-pregn-4-en-3-one) or 20β-dihydroprogesterone (20β-hydroxy-pregn-4-en-3-one) from the perfusates, adrenals and livers failed. No labelled cortisol (11β,17,21-trihydroxy-pregn-4-ene-3,20-dione) or corticosterone (11β,21-dihydroxy-pregn-4-ene-3,20-dione) was detected in the adrenals, and no testosterone, oestrone (3-hydroxy-oestra-1,3,5(10)-trien-17-one) or 16α-hydroxy-dehydroepiandrosterone (3β,16α-dihydroxy-androst-5-en-17-one) in the perfusates. Pregnenolone and dehydroepiandrosterone (which were present in approximately equal amounts) accounted for as much as 95% of all steroids isolated from all sources. The bulk of these two steroids was isolated from the perfusates. The 14C/3H ratio of the pregnenolone and dehydroepiandrosterone isolated from the conjugated fraction of the perfusates was much higher than that of the unconjugated compounds. It is concluded that the midgestation human foetus is capable per se of carrying out the de novo synthesis of major quantities of pregnenolone and dehydroepiandrosterone. It is suggested that in foetal steroidogenesis acetate is utilized predominantly via a conjugated pathway and circulating cholesterol mainly via an unconjugated pathway.

DE NOVO SYNTHESIS OF STEROIDS AND STEROID SULPHATES BY THE TESTICLES OF THE HUMAN FOETUS AT MIDGESTATION

1972 ◽  
Vol 71 (4) ◽  
pp. 792-800 ◽  
Author(s):  
R. S. Mathur ◽  
N. Wiqvist ◽  
E. Diczfalusy
Keyword(s):  
Sodium Acetate ◽  
De Novo ◽  
De Novo Synthesis ◽  
Human Foetus ◽  
Internal Standards ◽  
Human Foetuses

ABSTRACT The de novo synthesis of steroids and steroid sulphates by the testicles of four human foetuses at midgestation was studied. Two foetuses and two foeto-placental units were perfused at 36°C for 120 minutes with 3.0 and 6.0 mCi of [14C] sodium acetate, respectively. Radiochemically homogeneous steroids and steroid sulphates were isolated from the testicular extracts. Tritium labelled internal standards were used in order to assess procedural losses. No labelled steroids were detected in the testicular extracts in one case. From the testicles of each of the three other foetuses pregnenolone, pregnenolone sulphate, dehydroepiandrosterone, dehydroepiandrosterone sulphate, Δ5-androstenediol and testosterone were isolated. Progesterone and androstenedione were isolated in only one case each. Pregnenolone was found to be the predominant steroid formed. It is concluded that the testicles of midgestation human foetuses synthesize and secrete testosterone. It is likely that for the synthesis of this testosterone, the foetal testicles utilize preferentially the so-called Δ5-pathway.

PATHWAYS OF TESTOSTERONE SYNTHESIS IN DECAPSULATED TESTES OF MICE

1976 ◽  
Vol 81 (1) ◽  
pp. 170-184 ◽  
Author(s):  
B. de la Torre ◽  
G. Benagiano ◽  
E. Diczfalusy
Keyword(s):  
Leydig Cell ◽  
Incubation Medium ◽  
Sodium Acetate ◽  
De Novo ◽  
Acetate Incorporation ◽  
Dehydroepiandrosterone Sulphate ◽  
Carbon 14 ◽  
Adult Mice ◽  
17 Hydroxyprogesterone ◽  
Testosterone Synthesis

ABSTRACT In order to study the temporal relations in the biogenesis of testosterone, decapsulated testes of adult mice were incubated with carbon-14-labelled sodium acetate and attempts were made to isolate the most likely intermediates. Considerable quantities of radiochemically homogeneous squalene, lanosterol, cholesterol, testosterone and androstenedione, but no pregnenolone, progesterone, 17-hydroxypregnenolone, 17-hydroxyprogesterone, dehydroepiandrosterone, pregnenolone sulphate or dehydroepiandrosterone sulphate were isolated. The same pattern of incorporation was found when gradually increasing amounts of non-labelled pregnenolone, progesterone, 17-hydroxypregnenolone, 17-hydroxyprogesterone, dehydroepiandrosterone, dehydroepiandrosterone sulphate or testosterone were added to the system as "trapping agents" or when Leydig cell preparations rather than decapsulated testes were used. The presence of 10 mIU of HCG greatly enhanced the de novo formation of testosterone, androstenedione and 5α-dihydrotestosterone but did not change the pattern of acetate incorporation. Radioimmunoassays of the incubation medium with or without added HCG, and carried out at different periods of time indicated the presence of gradually increasing amounts of testosterone and androstenedione together with some 5α-dihydrotestosterone, whereas only trace amounts of pregnenolone, progesterone, 17-hydroxypregnenolone, 17-hydroxyprogesterone and dehydroepiandrosterone were present. An analysis of the incubated testes revealed that the addition of HCG significantly enhanced the content of testosterone, androstenedione and 5α-dihydrotestosterone. Little or no increase was observed as far as pregnenolone, progesterone, 17-hydroxypregnenolone, 17-hydroxyprogesterone or dehydroepiandrosterone were concerned. It is concluded that decapsulated testes of mice synthesize de novo testosterone from sodium acetate under conditions in which the formation of pregnenolone, progesterone, 17-hydroxypregnenolone, 17-hydroxyprogesterone, pregnenolone sulphate and 17-hydroxypregnenolone sulphate cannot be demonstrated.

QUANTITATIVE ASSESSMENT OF THE PRINCIPAL STEROIDS FORMED BY HUMAN PLACENTAS PERFUSED WITH LABELLED CHOLESTEROL IN VITRO

1973 ◽  
Vol 72 (1) ◽  
pp. 127-136 ◽  
Author(s):  
G. Telegdy ◽  
M. Robin ◽  
E. Diczfalusy
Keyword(s):  
Human Placenta ◽  
Quantitative Assessment ◽  
Internal Standards ◽  
Carbon 14 ◽  
The Individual

ABSTRACT Three midgestation and three term placentas were perfused in vitro each with 5 mCi of [7α-3H] cholesterol. Perfusions were carried out at 37°C for 120 minutes, using diluted blood oxygenated with an air + CO2 mixture (23.1% O2 + 3.6% CO2). Radiochemically homogenous pregnenolone, progesterone, dehydroepiandrosterone and 17β-oestradiol were isolated from each placenta and each perfusate. Carbon-14 labelled internal standards were used in order to assess procedural losses. On an average 0.01 per cent of the perfused cholesterol was converted to the four steroids studied by midgestation placentas and 0.015 per cent by term placentas. Approximately equal amounts of the individual steroids were recovered from the placentas and from the perfusates. The amounts of pregnenolone + progesterone isolated exceeded those of dehydroepiandrosterone + 17β-oestradiol by a factor of 7 to 8. It is suggested that the human placenta is capable of converting circulating cholesterol not only to pregnenolone and progesterone, but also to dehydroepiandrosterone and 17β-oestradiol.

IN VITRO STEROL AND STEROID SYNTHESIS BY OVARIES OF HYPOPHYSECTOMIZED IMMATURE RATS TREATED WITH HUMAN GONADOTROPHINS

1973 ◽  
Vol 73 (2) ◽  
pp. 321-334 ◽  
Author(s):  
R. Uma Bai ◽  
K. Bischoff ◽  
J. C. Macome ◽  
E. Diczfalusy
Keyword(s):  
Cholesteryl Esters ◽  
Cholesterol Esters ◽  
Steroid Synthesis ◽  
Internal Standards ◽  
Carbon 14 ◽  
Homogeneous Form ◽  
Immature Rats ◽  
Urinary Fsh

ABSTRACT The in vitro conversion of sodium [ 1,2- 14C] acetate into sterols and steroids was studied following the incubation of groups of ovaries from hypophysectomized immature rats with human gonadotrophins. Tritium labelled internal standards were used to monitor procedural losses and sterols and steroids were isolated in a radiochemically homogeneous form. The gonadotrophin preparations studied included a highly purified human urinary LH preparation (with no detectable FSH activity) as well as human urinary FSH and HCG preparations in which the LH and FSH-like activity, respectively, was selectively neutralized by the addition of appropriate antigonadotrophic sera. The ovaries of saline-treated control animals converted considerable quantities of labelled acetate into cholesterol and small amounts into cholesterol esters. Little, if any, acetate was converted by these ovaries into steroids. The injection of a human urinary LH-free FSH preparation or of a highly purified human urinary LH preparation resulted in a marked increase in the incorporation of labelled acetate into cholesterol, which was accompanied by a slightly increased incorporation into cholesteryl esters. Small amounts of carbon-14 labelled androstenedione and testosterone were also isolated but no pregnenolone or progesterone was found.

ACETATE AND CHOLESTEROL METABOLISM IN THE HUMAN FOETO-PLACENTAL UNIT AT MIDGESTATION

1970 ◽  
Vol 63 (1) ◽  
pp. 105-118 ◽  
Author(s):  
G. Telegdy ◽  
J. W. Weeks ◽  
N. Wiqvist ◽  
E. Diczfalusy
Keyword(s):  
Human Placenta ◽  
Sodium Acetate ◽  
De Novo ◽  
Cholesterol Metabolism ◽  
Steroid Synthesis ◽  
Homogeneous Form

ABSTRACT Two midgestation placentas were perfused with 2.5 mCi of uniformly labelled 14C-sodium acetate plus 2.5 mCi cholesterol-7α-3H. and two complete foeto-placental units were perfused with 5.0 mCi of 14C-labelled sodium acetate plus 5.0 mCi of cholesterol-7α-3H. The perfusions were carried out at 35–36°C for 90 min. After the perfusion of the isolated placentas, the following 3H-labelled steroids were isolated from the placentas as well as from the perfusates in a radiochemically homogeneous form: pregnenolone (3β-hydroxy-pregn-5-en-20-one), progesterone (pregn-4-ene-3,20-dione), 20α-dihydroprogesterone (20α-hydroxy-pregn-4-en-3-one), 20β-dihydroprogesterone (20β-hydroxy-pregn-4-en-3-one), 17α-hydroxy-pregnenolone (3β,17α-dihydroxy-pregn-5-en-20-one),dehydroepiandrosterone(3β-hydroxy-androst-5-en-17-one) and 17β-oestradiol (oestra-1,3,5(10)-triene-3,17β-diol). The same compounds were also isolated from the placentas following the perfusion of the complete foeto-placental units. With the exception of pregnenolone and progesterone, all steroids were isolated in minute quantities. None of the steroids isolated contained any 14C-label. It is concluded that the midgestation human placenta is not capable of carrying out any de novo steroid synthesis from acetate and that cholesterol is an obligatory precursor in placental steroidogenesis.

IN VITRO STEROL AND STEROID BIOGENESIS BY A FEMINIZING ADRENOCORTICAL CARCINOMA

1973 ◽  
Vol 73 (3) ◽  
pp. 518-530 ◽  
Author(s):  
R. S. Mathur ◽  
H. O. Williamson ◽  
L. O. Moody ◽  
E. Diczfalusy
Keyword(s):  
Adrenocortical Carcinoma ◽  
Sodium Acetate ◽  
De Novo ◽  
Isotopic Ratio ◽  
Menopausal Woman ◽  
Isotopic Ratios ◽  
Carbon 14 ◽  
In Parenthesis ◽  
Post Menopausal

ABSTRACT A post-menopausal woman was found to excrete elevated amounts of urinary oestrogens. An adrenal carcinoma was removed and slices incubated in phosphate buffer, pH 7.4 with [14C] sodium acetate in combination with either [7α-3H] cholesterol, [7α-3H]dehydroepiandrosterone or [7α-3H]androstenedione. Radiochemically homogeneous tritium labelled oestrone, 17β-oestradiol and oestriol were isolated in each of the three experiments. Carbon-14 activity was incorporated into oestrone in each of the three experiments and into oestriol in one case only. No carbon-14 activity was associated with 17β-oestradiol isolated from any of the three incubations. Oestrone was found to be the predominant oestrogen synthesized in all experiments. When [14C]sodium acetate and [7α-3H]cholesterol (3H/14C ratio = 0.61) were used as substrates, the following compounds were isolated in a radiochemically homogeneous form (the isotopic ratio in each being shown in parenthesis): cholesterol (13.0), cholesterol sulphate (1.6), pregnenolone (1.0), pregnenolone sulphate (0.2), dehydroepiandrosterone (3.2), dehydroepiandrosterone sulphate (1.2), Δ5-androstenediol (3.1), Δ5-androstenediol sulphate (isolated as the unconjugated compound following solvolysis of the "disulphate" fraction (0.6), testosterone (1.1), testosterone sulphate (0.6), and oestrone (1.3). It is concluded that the adrenocortical carcinoma studied was capable of synthesizing oestrone, oestriol and cholesterol sulphate de novo from acetate, and that the steroidogenic processes led to the predominant formation of Δ5-steroid sulphates. Furthermore, a comparison of the isotopic ratios in the various compounds isolated suggests that a number of unusual transformations may have occurred during steroidogenesis by the tumour cells in vitro.

DE NOVO SYNTHESIS OF STEROIDS BY THE TESTES OF THE HUMAN FOETUS AT MIDGESTATION

1971 ◽  
Vol 68 (1_Supplb) ◽  
pp. S135 ◽  
Author(s):  
R. S. Mathur ◽  
N. Wiqvist ◽  
E. Diczfalusy
Keyword(s):  
De Novo ◽  
De Novo Synthesis ◽  
Human Foetus
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