AROMATIZING ACTIVITY OF PLACENTAL MICROSOMAL FRACTIONS FROM EWES IN LATE GESTATION

1975 ◽  
Vol 65 (1) ◽  
pp. 117-125 ◽  
Author(s):  
M. R. MANN ◽  
L. B. CURET ◽  
A. E. COLAS
Keyword(s):  
Sharp Increase ◽  
Enzyme System ◽  
Hydroxysteroid Dehydrogenase ◽  
Relative Increase ◽  
Late Gestation ◽  
Domestic Sheep ◽  
Dramatic Rise ◽  
Oestradiol Production ◽  
Human Placentae

SUMMARY Placental microsomes from eight domestic sheep at 136–146 days of gestation were incubated with radioactive androstenedione, testosterone and dehydroepiandrosterone. Aromatizing activity was examined in the presence and absence of cortisol and the rates of both oestrone and oestradiol synthesis were measured. Oestrone predominated in preference to oestradiol in most of the incubations, a result opposite to that found with human placentae. The sharp increase in the rate of oestradiol production found in the 144- to 146-day-old placentae incubated with testosterone may indicate a more rapid increase of aromatizing than of 17β-hydroxysteroid dehydrogenase activity. The presence of cortisol in the mixtures did not significantly affect the placental aromatizing activity, indicating that there is no direct effect of cortisol on the enzyme system as measured in vitro. The dramatic rise of overall mean aromatizing activity from 4·86 ± 0·22 (s.e.m.) at 138–141 days of gestation to 12·96 ± 0·38 pmol/mg protein/min at 144–146 days (with a greater relative increase in the rate of oestradiol formation), suggests that changes in placental aromatizing activity may play an important role in maternal and foetal plasma oestrogen surges before ovine parturition.

IN VITRO STEROID SYNTHESIS BY FOETAL RABBIT ADRENALS

1971 ◽  
Vol 68 (2) ◽  
pp. 209-218 ◽  
Author(s):  
K. Kurachi ◽  
M. Miyazaki ◽  
H. Mori ◽  
K. Matsumoto
Keyword(s):  
Isotope Dilution ◽  
Hydroxysteroid Dehydrogenase ◽  
Late Gestation ◽  
Cortical Tissue ◽  
Steroid Synthesis ◽  
Metabolic Pattern ◽  
Adrenal Tissue ◽  
Tissue Homogenates

ABSTRACT Adrenal tissue homogenates from foetal rabbits in late gestation and their mothers were incubated with [7α-3H] pregnenolone and analyzed for conversion products by reverse isotope dilution procedures. Deoxycorticosterone and corticosterone were synthesized as main products by foetal as well as by adult adrenals. In addition, small amounts of progesterone, 17-hydroxypregnenolone and cortisol were formed by both adrenals. No C19-steroids and 16α-hydroxysteroids could be found. The results indicate a similarity in the qualitative metabolic pattern of pregnenolone by adrenal cortical tissue of late gestation rabbit foetuses to that of adult rabbits. However, the activity of 3β-hydroxysteroid dehydrogenase per gram tissue in the foetal rabbit adrenal was of the order of one tenth that in the adrenals of their mothers. By using [3H] progesterone as substrate, the activities of 21-hydroxylase and 11β-hydroxylase in the foetal adrenal were similarly demonstrated to be less than that of the adrenal of the mother.

CONVERSION OF PREGNENOLONE TO PROGESTERONE BY RABBIT PLACENTA IN VITRO

1969 ◽  
Vol 61 (4) ◽  
pp. 577-584 ◽  
Author(s):  
K. Matsumoto ◽  
G. Yamane ◽  
H. Endo ◽  
K. Kotoh ◽  
K. Okano
Keyword(s):  
Isotope Dilution ◽  
Specific Activity ◽  
Enzyme System ◽  
Hydroxysteroid Dehydrogenase ◽  
Pregnant Rabbit ◽  
Dehydrogenase Enzyme ◽  
Constant Specific Activity

ABSTRACT A placental preparation from rabbits in mid-pregnancy was shown to convert 7α-3H-pregnenolone to radioactive progesterone in vitro. The extent of conversion per gram tissue by the placenta was about one hundredth of that by the ovary from the pregnant rabbit. Identification of radioactive progesterone was accomplished by reverse isotope dilution and recrystallization to constant specific activity. However, no Δ5-3β-hydroxysteroid dehydrogenase was found histochemically in the trophoblast and other tissues of the rabbit placenta. No ability to convert 7α-3H-pregnenolone to radioactive 20α-hydroxypregn-4-en-3-one, 20β-hydroxypregn-4-en-3-one, corticosterone, cortisol, androst-4-ene-3,17-dione, dehydroepiandrosterone, 17β-oestradiol and oestrone in placental preparation from rabbits could be demonstrated. The data demonstrate the presence of a 3β-ol-dehydrogenase enzyme system in the rabbit placenta.

Oxygenation of 18-hydroxycorticosterone as the final reaction for aldosterone biosynthesis

1984 ◽  
Vol 107 (3) ◽  
pp. 395-400 ◽  
Author(s):  
Itaru Kojima ◽  
Etsuro Ogata ◽  
Hiroshi Inano ◽  
Bun-ichi Tamaoki
Keyword(s):  
Carbon Monoxide ◽  
Hydroxysteroid Dehydrogenase ◽  
Dependent Manner ◽  
In Vitro Production ◽  
Mitochondrial Preparation ◽  
Final Reaction ◽  
Vitro Production ◽  
Dose Dependent ◽  
Cytochrome P 450

Abstract. Incubation of 18-hydroxycorticosterone with the sonicated mitochondrial preparation of bovine adrenal glomerulosa tissue leads to the production of aldosterone, as measured by radioimmunoassay. The in vitro production of aldosterone from 18-hydroxycorticosterone requires both molecular oxygen and NADPH, and is inhibited by carbon monoxide. Cytochrome P-450 inhibitors such as metyrapone, SU 8000. SU 10603, SKF 525A, amphenone B and spironolactone decrease the biosynthesis of aldosterone from 18-hydroxycorticosterone. These results support the conclusion that the final reaction in aldosterone synthesis from 18-hydroxycorticosterone is catalyzed by an oxygenase, but not by 18-hydroxysteroid dehydrogenase. By the same preparation, the production of [3H]aldosterone but not [3H]18-hydroxycorticosterone from [1,2-3H ]corticosterone is decreased in a dose-dependent manner by addition of non-radioactive 18-hydroxycorticosterone.

Decreases in ovine fetal cartilage sulfate uptake and serum sulfate during gestation

1985 ◽  
Vol 249 (1) ◽  
pp. E115-E120
Author(s):  
F. H. Morriss ◽  
R. N. Marshall ◽  
S. S. Crandell ◽  
B. J. Fitzgerald ◽  
L. Riddle
Keyword(s):  
Human Serum ◽  
Costal Cartilage ◽  
Full Term ◽  
Late Gestation ◽  
In Vitro Assays ◽  
Sulfate Uptake ◽  
Fetal Sheep ◽  
Ovine Fetal ◽  
Serum Sulfate

In vitro assays for [35S]sulfate uptake by ovine fetal costal cartilage were used to assess gestational changes in cartilage metabolism. Addition of 20% normal human serum to the incubation medium increased fetal cartilage [35S]sulfate incorporation into glycosaminoglycans. Both basal and human serum-stimulated uptakes of [35S]sulfate by fetal sheep cartilage decreased from midgestation to full term. The incremental response in [35S]sulfate uptake that was stimulated by human serum decreased as gestation proceeded to full-term. Fetal serum sulfate concentration decreased logarithmically during gestation, raising the possibility that cartilage sulfate uptake might become substrate limited as full term is approached. Perfusion of seven late gestation sheep fetuses for 7 days with Na2SO4 to achieve serum sulfate concentrations similar to those observed earlier in gestation resulted in a 33% increase in mean cartilage [35S]sulfate uptake compared with that of control twin fetuses, but uptake was not increased to values that occurred spontaneously earlier in gestation. These results suggest that the decreasing rate of [35S]sulfate uptake by fetal cartilage during the last half of gestation is associated only minimally with decreasing serum sulfate levels and is most consistent with intrinsic change in resting chondrocyte metabolism during gestation.

scholarly journals Non-invasive skin sampling of tryptophan/kynurenine ratio in vitro towards a skin cancer biomarker

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Skaidre Jankovskaja ◽  
Johan Engblom ◽  
Melinda Rezeli ◽  
György Marko-Varga ◽  
Tautgirdas Ruzgas ◽  
...  
Keyword(s):  
Skin Cancer ◽  
Relative Increase ◽  
Cancer Biomarker ◽  
Cancer Diagnostics ◽  
Sampling Time ◽  
Skin Permeability ◽  
Experimental Conditions ◽  
Non Invasive

AbstractThe tryptophan to kynurenine ratio (Trp/Kyn) has been proposed as a cancer biomarker. Non-invasive topical sampling of Trp/Kyn can therefore serve as a promising concept for skin cancer diagnostics. By performing in vitro pig skin permeability studies, we conclude that non-invasive topical sampling of Trp and Kyn is feasible. We explore the influence of different experimental conditions, which are relevant for the clinical in vivo setting, such as pH variations, sampling time, and microbial degradation of Trp and Kyn. The permeabilities of Trp and Kyn are overall similar. However, the permeated Trp/Kyn ratio is generally higher than unity due to endogenous Trp, which should be taken into account to obtain a non-biased Trp/Kyn ratio accurately reflecting systemic concentrations. Additionally, prolonged sampling time is associated with bacterial Trp and Kyn degradation and should be considered in a clinical setting. Finally, the experimental results are supported by the four permeation pathways model, predicting that the hydrophilic Trp and Kyn molecules mainly permeate through lipid defects (i.e., the porous pathway). However, the hydrophobic indole ring of Trp is suggested to result in a small but noticeable relative increase of Trp diffusion via pathways across the SC lipid lamellae, while the shunt pathway is proposed to slightly favor permeation of Kyn relative to Trp.

Effects of Maternal Nutrient Restriction During Gestation on LH Production in the Female Bovine Fetus

2021 ◽  
Vol 99 (Supplement_2) ◽  
pp. 25-26
Author(s):  
Sterling H Fahey ◽  
Sarah West ◽  
John M Long ◽  
Carey Satterfield ◽  
Rodolfo C Cardoso
Keyword(s):  
Protein Content ◽  
Fetal Development ◽  
Monozygotic Twins ◽  
Late Gestation ◽  
Nutrient Restriction ◽  
Western Blots ◽  
Physiological Processes ◽  
Individual Potential ◽  
The Individual

Abstract Gestational nutrient restriction causes epigenetic and phenotypic changes that affect multiple physiological processes in the offspring. Gonadotropes, the cells in the anterior pituitary that secrete luteinizing hormone (LH) and follicle-stimulating hormone (FSH), are particularly sensitive to nutritional changes during fetal development. Our objective herein was to investigate the effects of gestational nutrient restriction on LH protein content and number of gonadotropes in the fetal bovine pituitary. We hypothesized that moderate nutrient restriction during mid to late gestation decreases pituitary LH production, which is associated with a reduced number of gonadotropes. Embryos were produced in vitro with X-bearing semen from a single sire then split to generate monozygotic twins. Each identical twin was transferred to a virgin dam yielding four sets of female twins. At gestational d 158, the dams were randomly assigned into two groups, one fed 100% NRC requirements (control) and the other fed 70% of NRC requirements (restricted) during the last trimester of gestation, ensuring each pair of twins had one twin in each group. At gestational d 265, the fetuses (n = 4/group) were euthanized by barbiturate overdose, and the pituitaries were collected. Western blots were performed using an ovine LH-specific antibody (Dr. A.F. Parlow, NIDDK). The total LH protein content in the pituitary tended to be decreased in the restricted fetuses compared to controls (P < 0.10). However, immunohistochemistry analysis of the pituitary did not reveal any significant changes in the total number of LH-positive cells (control = 460±23 cells/0.5 mm2; restricted = 496±45 cells/0.5 mm2, P = 0.58). In conclusion, while maternal nutrient restriction during gestation resulted in a trend of reduced LH content in the fetal pituitary, immunohistological findings suggest that these changes are likely related to the individual potential of each gonadotrope to produce LH, rather than alterations in cell differentiation during fetal development.

STIMULATION BY HUMAN CHORIONIC GONADOTROPHIN OF OESTRADIOL PRODUCTION BY DISPERSED CELLS FROM HUMAN CORPUS LUTEUM: COMPARISON WITH PROGESTERONE PRODUCTION; UTILIZATION OF EXOGENOUS TESTOSTERONE

1981 ◽  
Vol 91 (2) ◽  
pp. 197-203 ◽  
Author(s):  
M. C. RICHARDSON ◽  
G. M. MASSON
Keyword(s):  
Luteal Phase ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Cell Suspensions ◽  
Corpora Lutea ◽  
Progesterone Production ◽  
Late Luteal Phase ◽  
Oestradiol Production ◽  
Dispersed Cells

Cell suspensions were prepared from tissue samples of human corpora lutea obtained during the mid- and late-luteal phase of the menstrual cycle. Both oestradiol and progesterone production by dispersed cells were stimulated by similar concentrations of human chorionic gonadotrophin (hCG). As the degree of stimulation of production by hCG was greater for progesterone than for oestradiol (five- to tenfold compared with two- to threefold higher than basal production), the ratio of progesterone to oestradiol produced varied according to the level of trophic stimulation. A comparison of cell suspensions prepared from mid- and late-luteal phase corpora lutea, exposed to the same concentration of hCG (10 i.u./ml) in vitro, did not reveal a shift to oestradiol production in the late-luteal phase. Provision of additional testosterone during incubation raised the level of oestradiol production by dispersed luteal cells. At an optimum concentration of testosterone (1 μmol/l), oestradiol synthesis was not raised further in the presence of hCG or N6, O2-dibutyryl cyclic AMP, suggesting a lack of induction or activation of the aromatase system by gonadotrophin in short-term cultures. Basal and stimulated levels of progesterone production were not significantly impaired in the presence of testosterone.

In vitro biosynthesis of steroid sulfates by cell-free preparations from tissues of the laying hen

1968 ◽  
Vol 46 (8) ◽  
pp. 749-757 ◽  
Author(s):  
H. R. Raud ◽  
R. Hobkirk
Keyword(s):  
Enzyme System ◽  
Laying Hen ◽  
Product Identification ◽  
Temperature Requirements ◽  
Before And After ◽  
Liver Preparation ◽  
Steroid Sulfate ◽  
In Vitro Biosynthesis ◽  
Estradiol 17Β

The sulfurylation of estrone-6,7-3H, estradiol-17β-6,7-3H, and dehydroisoandrosterone-4-14C by laying hen liver, oviduct, and vaginal preparations was investigated. Purification and product identification included ether and ethyl acetate extraction, paper chromatography, and isotope dilution, before and after hydrolysis with a sulfatase preparation.The esterifying enzymes were found in the 105 000 × g supernatants of the three tissues. The liver preparation was many times more active in steroid sulfate synthesis than the corresponding oviduct or vaginal fractions. Sulfurylation of dehydroisoandrosterone displayed the same cofactor, pH, and temperature requirements as did that of estrone and estradiol-17β. The degree of dehydroisoandrosterone sulfate synthesis was considerably lower than that of the estrogens, however. It is suggested that the laying hen possesses an enzyme system which is more efficient for the sulfurylation of estrogens than of other steroids such as dehydroisoandrosterone.

Enzyme system of Clostridium stercorarium for hydrolysis of arabinoxylan: reconstitution of the in vivo system from recombinant enzymes

Microbiology ◽  
2004 ◽  
Vol 150 (7) ◽  
pp. 2257-2266 ◽  
Author(s):  
Helmuth Adelsberger ◽  
Christian Hertel ◽  
Erich Glawischnig ◽  
Vladimir V. Zverlov ◽  
Wolfgang H. Schwarz
Keyword(s):  
Extracellular Enzymes ◽  
Enzyme System ◽  
Thermophilic Bacterium ◽  
Recombinant Enzymes ◽  
Type Mode ◽  
Complete Set ◽  
First Time ◽  
Hydrolysis Of

Four extracellular enzymes of the thermophilic bacterium Clostridium stercorarium are involved in the depolymerization of de-esterified arabinoxylan: Xyn11A, Xyn10C, Bxl3B, and Arf51B. They were identified in a collection of eight clones producing enzymes hydrolysing xylan (xynA, xynB, xynC), β-xyloside (bxlA, bxlB, bglZ) and α-arabinofuranoside (arfA, arfB). The modular enzymes Xyn11A and Xyn10C represent the major xylanases in the culture supernatant of C. stercorarium. Both hydrolyse arabinoxylan in an endo-type mode, but differ in the pattern of the oligosaccharides produced. Of the glycosidases, Bxl3B degrades xylobiose and xylooligosaccharides to xylose, and Arf51B is able to release arabinose residues from de-esterified arabinoxylan and from the oligosaccharides generated. The other glycosidases either did not attack or only marginally attacked these oligosaccharides. Significantly more xylanase and xylosidase activity was produced during growth on xylose and xylan. This is believed to be the first time that, in a single thermophilic micro-organism, the complete set of enzymes (as well as the respective genes) to completely hydrolyse de-esterified arabinoxylan to its monomeric sugar constituents, xylose and arabinose, has been identified and the enzymes produced in vivo. The active enzyme system was reconstituted in vitro from recombinant enzymes.

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