SQUALENE AND LANOSTEROL SYNTHESIS IN THE FOETO-PLACENTAL UNIT AT MIDGESTATION

1971 ◽  
Vol 66 (4) ◽  
pp. 711-719 ◽  
Author(s):  
H. A. van Leusden ◽  
M. Siemerink ◽  
G. Telegdy ◽  
E. Diczfalusy
Keyword(s):  
Human Placenta ◽  
Sodium Acetate ◽  
Human Foetus ◽  
Minute Amount ◽  
Chromatographic Evidence

ABSTRACT In order to investigate the synthesis of squalene and lanosterol in the human foeto-placental unit at midgestation, two complete foeto-placental units, two isolated midgestation foetuses and two isolated midgestation placentas were perfused with [14C] sodium acetate immediately following their removal at laparotomy. The perfusions were carried out at 36°C for 90 minutes, administering 5.0 mCi (foeto-placental units), or 2.5 mCi (separate perfusions of foetuses or placentas) amounts of [14C] sodium acetate. Chromatographic evidence indicated the presence of [14C] squalene-like material in the extracts of all adrenals and livers. Radiochemically homogeneous squalene was isolated in the form of squalene dodecabromide from one adrenal and two liver extracts, which were studied more in detail. In the extracts of all placentas, testicles, carcasses and perfusates, the presence of any [14C] squalene was excluded by crystallization. Sufficient material for the identification of [14C] lanosterol was present in the extracts of three adrenals, three livers, four testicles and two carcasses. From all these extracts radiochemically homogeneous [14C]-lanosterol was isolated. The [14C] lanosterol-like material present in all perfusates was so limited that it precluded further identification. In the extracts of three placentas, the presence of any [14C] lanosterol was excluded by crystallization. From the extract of a separately perfused placenta a minute amount of radiochemically homogeneous [14C] lanosterol was isolated. It is concluded that the midgestation human foetus is capable of synthesizing major quantities of squalene and lanosterol. Little, if any, squalene and lanosterol are formed by the midgestation human placenta.

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

1970 ◽  
Vol 63 (1) ◽  
pp. 91-104 ◽  
Author(s):  
G. Telegdy ◽  
J. W. Weeks ◽  
U. Lerner ◽  
G. Stakemann ◽  
E. Diczfalusy
Keyword(s):  
Human Placenta ◽  
Metabolic Pathway ◽  
Sodium Acetate ◽  
Cholesterol Metabolism ◽  
The Other ◽  
Human Foetus ◽  
Homogeneous Form ◽  
Other Hand ◽  
Maternal Side

ABSTRACT As the first part of a series of investigations on acetate and cholesterol metabolism, the conversion of acetate to cholesterol was studied in the various compartments of the midgestation foeto-placental unit in perfusion experiments carried out for 90 min at 35–36°C. Following their removal at laparotomy two complete foeto-placental units were perfused each with 5.0 mCi of uniformly labelled sodium acetate-14C + 5.0 mCi of cholesterol-7α-3H. The study was completed by the separate perfusion of two isolated midgestation foetuses and two midgestation placentas. The doses administered in each of these four last experiments were 2.5 mCi of 14C-labelled acetate and 2.5 mCi of 3H-labelled cholesterol. Cholesterol was isolated in a radiochemically homogeneous form from each of the tissues studied. The cholesterol isolated from the placentas, placental perfusates and from the blood bathing the placenta from the maternal side (»maternal perfusates«) contained exclusively 3H-label. On the other hand, the cholesterol isolated from all foetal livers, adrenals, testicles, 3 of 4 residual foetal tissues and 1 out of 4 foetal perfusates also contained significant quantities of 14C-label. It is concluded, that the midgestation human placenta is not capable of synthesizing cholesterol from acetate, but that the conversion of acetate to cholesterol is a quantitatively significant metabolic pathway in the human foetus at midgestation.

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.

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.

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.

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.

scholarly journals Purification and properties of N-acetylgalactosamine 6-sulphate sulphatase from human placenta

1979 ◽  
Vol 181 (1) ◽  
pp. 37-46 ◽  
Author(s):  
Josef Glössl ◽  
Wolfgang Truppe ◽  
Hans Kresse
Keyword(s):  
Human Placenta ◽  
Sodium Acetate ◽  
Heparan Sulphate ◽  
Sodium Dodecyl ◽  
Acetate Buffer ◽  
Major Protein ◽  
Sodium Acetate Buffer ◽  
Ph Optimum ◽  
Enzyme Preparations ◽  
Major Protein Band

1. N-Acetylgalactosamine 6-sulphate sulphatase was purified about 20000-fold from the soluble extract of human placenta with N-acetylgalactosamine 6-sulphate–glucuronic acid–N-acetyl[1-3H]galactosaminitol 6-sulphate as substrate in the activity assay. The enzyme appears to be a glycoprotein with a mol.wt. of about 100000 as determined by gel filtration. On gel electrophoresis in the presence of sodium dodecyl sulphate the major protein band had a mol.wt. of 78000. Variable charge heterogeneity was observed in several enzyme preparations. 2. The purified enzyme released up to one sulphate molecule from the disulphated trisaccharide. It was active towards N-acetylgalactosamine 6-sulphate and exhibited no measurable N-acetylglucosamine 6-sulphate sulphatase or any other known lysosomal sulphatase activity. Hydrolysis of [1-3H]galactitol 6-sulphate was achieved by incubation neither with a crude nor with a purified enzyme preparation. Chondroitin 6-sulphate and keratan sulphate, as well as heparin and heparan sulphate, served as competitive inhibitors of the enzyme. 3. Purified N-acetylgalactosamine 6-sulphate sulphatase activity was optimal at pH4.9 and 4.4 when assayed in 0.02m-sodium acetate buffer and at pH4.2 and 5.2 in 0.1m-sodium acetate buffer. A single pH-optimum at pH4.8 was observed for the crude enzyme and for the purified enzyme after mild periodate treatment. The sulphatase activity was inhibited by a variety of anions and cations and activated by thiol-specific and thiol reagents.

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.

Scanning Electron Microscopic Study of the Cell Surface

1969 ◽  
Vol 27 ◽  
pp. 36-37 ◽  
Author(s):  
Toichiro Kuwabara
Keyword(s):  
Tissue Fluid ◽  
Biological Application ◽  
Biological Structure ◽  
Electron Microscopic ◽  
Surface Appearance ◽  
Minute Amount ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
True Structure ◽  
Scanning Electron

Although scanning electron microscopy has a great potential in biological application, there are certain limitations in visualization of the biological structure. Satisfactory techniques to demonstrate natural surfaces of the tissue and the cell have been reported by several investigators. However, it is commonly found that the surface cell membrane is covered with a minute amount of mucin, secretory substance or tissue fluid as physiological, pathological or artefactual condition. These substances give a false surface appearance, especially when the tissue is fixed with strong fixatives. It seems important to remove these coating substances from the surface of the cell for demonstration of the true structure.

The role of silicon in forages: A quantitative X-Ray study

1987 ◽  
Vol 45 ◽  
pp. 416-417
Author(s):  
Janet H. Woodward ◽  
D. E. Akin
Keyword(s):  
Sodium Acetate ◽  
Dry Matter ◽  
Acetate Buffer ◽  
Plant Tissues ◽  
Sodium Acetate Buffer ◽  
X Ray ◽  
Dry Matter Digestibility ◽  
Percent Composition

Silicon (Si) is distributed throughout plant tissues, but its role in forages has not been clarified. Although Si has been suggested as an antiquality factor which limits the digestibility of structural carbohydrates, other research indicates that its presence in plants does not affect digestibility. We employed x-ray microanalysis to evaluate Si as an antiquality factor at specific sites of two cultivars of bermuda grass (Cynodon dactvlon (L.) Pers.). “Coastal” and “Tifton-78” were chosen for this study because previous work in our lab has shown that, although these two grasses are similar ultrastructurally, they differ in in vitro dry matter digestibility and in percent composition of Si.Two millimeter leaf sections of Tifton-7 8 (Tift-7 8) and Coastal (CBG) were incubated for 72 hr in 2.5% (w/v) cellulase in 0.05 M sodium acetate buffer, pH 5.0. For controls, sections were incubated in the sodium acetate buffer or were not treated.

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