Kinetic comparison of the 3β-hydroxysteroid dehydrogenase activity in human placenta, chorion laeve, and ovary

1985 ◽  
Vol 63 (3) ◽  
pp. 183-186 ◽  
Author(s):  
W. Gibb ◽  
J. C. Lavoie ◽  
M. Morin-Gonthier
Keyword(s):  
Kinetic Parameters ◽  
Dehydrogenase Activity ◽  
Human Placenta ◽  
Hydroxysteroid Dehydrogenase ◽  
The Other ◽  
Human Tissues ◽  
Other Hand ◽  
Chorion Laeve ◽  
Human Ovaries ◽  
Nanomolar Range

Recent studies from our laboratory and others have shown that Km values for steroid substrates of the 3β-hydroxysteroid dehydrogenase in the human placenta were in the nanomolar range compared with micromolar values previously described. The purpose of the present study was to measure the kinetic parameters of the 3β -hydroxysteroid dehydrogenase in other human tissues, namely the ovary and chorion laeve, and to determine whether they were similar to those of the placental enzyme. In chorion laeve microsomes the 3β-hydroxysteroid dehydrogenase had Km values for dehydroepiandrosterone and pregnenolone similar to those found in placenta. Microsomes from human ovaries, on the other hand, had Km values for both substrates 10- to 20-fold higher. However, the ability of various steroids to inhibit the ovarian enzyme was similar to that previously described from the placenta and the chorion laeve.

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

1998 ◽  
Vol 83 (10) ◽  
pp. 3695-3701 ◽  
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.

11β-hydroxysteroid dehydrogenase activity (E.C. 1.1.1.146) in human placenta and decidua

1980 ◽  
Vol 13 (9) ◽  
pp. 1081-1087 ◽  
Author(s):  
A.López Bernal ◽  
A.P.F. Flint ◽  
A.B.M. Anderson ◽  
A.C. Turnbull
Keyword(s):  
Dehydrogenase Activity ◽  
Human Placenta ◽  
Hydroxysteroid Dehydrogenase

ANDROGEN METABOLISM IN THE EPITHELIAL AND STROMAL COMPONENTS OF THE HUMAN HYPERPLASTIC PROSTATE

1981 ◽  
Vol 91 (1) ◽  
pp. 23-32 ◽  
Author(s):  
F. K. HABIB ◽  
ANN L. TESDALE ◽  
G. D. CHISHOLM ◽  
A. BUSUTTIL
Keyword(s):  
Prostate Gland ◽  
Hydroxysteroid Dehydrogenase ◽  
Enzymatic Activities ◽  
The Other ◽  
Asymmetric Distribution ◽  
Androgen Metabolism ◽  
Main Site ◽  
Other Hand

The reduced and oxidized metabolites of testosterone and dihydrotestosterone were measured in the stromal and epithelial components of 23 human hyperplastic prostates. Our studies indicate differences in the hormonal metabolic patterns of the stroma and epithelium of the resected specimens when compared with tissues obtained retropubically. Testosterone 5α-reductase was evenly distributed between the two components of the specimens obtained retropubically whereas the 3α(β)-hydroxysteroid dehydrogenase was predominantly located in the stroma. The measurements on the resected specimens suggest, on the other hand, that the bulk of the 5α-reductase and 3α(β)-hydroxysteroid dehydrogenase activities were confined to the stroma although these activities were considerably lower than those measured in the corresponding components of the retropubically obtained specimens. The conversion of testosterone to androstenedione was negligible in all the samples analysed. We therefore conclude that the stroma is the main site for the transformation of dihydrotestosterone to the androstanediol epimers and that the asymmetric distribution of the 3α(β)-hydroxysteroid dehydrogenase may be instrumental in the development of hyperplasia in the prostate gland. Furthermore, the results of this study indicate that electro-resection impairs the enzymatic activities of the tissue.

3β-HYDROXYSTEROID DEHYDROGENASE ACTIVITY IN THE MOUSE OVARY

1965 ◽  
Vol 32 (3) ◽  
pp. 365-371 ◽  
Author(s):  
M. M. FERGUSON
Keyword(s):  
Dehydrogenase Activity ◽  
Hydroxysteroid Dehydrogenase ◽  
The Other ◽  
Interstitial Tissue ◽  
Corpora Lutea ◽  
Mouse Ovary ◽  
Colour Reaction ◽  
Theca Interna

SUMMARY Sections of ovaries from 30 Swiss white mice were incubated with ten steroid substrates to demonstrate 3β-hydroxysteroid dehydrogenase activity histochemically. The substrates were: (1) 3β-hydroxypregn-5-en-20-one (pregnenolone), (2) 3β,17α-dihydroxypregn-5-en-20-one (17α-hydroxypregnenolone), (3) 3β-hydroxyandrost-5-en-17-one (DHA), (4) 3β,17β-dihydroxyandrost-5-ene (androstenediol), (5) 3β-sulphoxypregn-5-en-20-one (pregnenolone sulphate), (6) 3β-sulphoxy-17α-hydroxypregn-5-en-20-one (17α-hydroxypregnenolone sulphate), (7) 3β-sulphoxyandrost-5-en-17-one (DHA sulphate), (8) 3β-acetoxypregn-5-en-20-one (pregnenolone acetate), (9) 3β-acetoxyandrost-5-en-17-one (DHA acetate), and (10) 3β-acetoxy-17β-hydroxyandrost-5-ene (androstenediol acetate). Pregnenolone, 17α-hydroxypregnenolone, DHA and androstenediol gave a colour reaction in the corpora lutea, interstitial tissue, theca interna and stroma of all ovaries examined. The granulosa of many follicles, some thought to be atretic, also contained diformazan granules. 17α-Hydroxypregnenolone did not give as intense a reaction as the other free steroids. No diformazan was deposited with DHA sulphate as substrate. Pregnenolone sulphate and 17α-hydroxypregnenolone sulphate were used by the same tissues as were the free steroids, although they were much less well utilized. Utilization of 3β-acetoxy derivatives was similar to that of the free steroids.

THE POLYCYSTIC OVARY. VIII.

1967 ◽  
Vol 56 (2) ◽  
pp. 255-271 ◽  
Author(s):  
Leonard R. Axelrod ◽  
Joseph W. Goldzieher
Keyword(s):  
Dehydrogenase Activity ◽  
Normal Tissue ◽  
Polycystic Ovary ◽  
Pure Form ◽  
The Other ◽  
Polycystic Ovaries ◽  
Experimental Conditions ◽  
Normal Cycle ◽  
Other Hand

ABSTRACT Tissue from one normal (cycle day 10) and 5 polycystic ovaries was incubated with radioactive pregnenolone, progesterone, testosterone, androstenedione or oestrone, and the metabolites isolated in radiochemically pure form. The patterns of pregnenolone metabolites with polycystic tissue differed from one another and from that of normal ovarian mince. Conversion of the substrate was generally much greater with the former, and in one instance the cortical portion was much more active than the medulla. 3β-ol dehydrogenase activity was markedly decreased in one case. 19-Oxygenation was seen infrequently and no aromatization was observed. On the other hand, 16-hydroxylation and 20-reduction were occasionally very prominent. Incubation of normal tissue with C19 precursors yielded oestrogen whereas polycystic tissue did not. The pathways androstenedione→testosterone→oestradiol and testosterone→16-hydroxy-testosterone→oestriol are suggested by the metabolites of the normal tissue. Under the experimental conditions, the reduction of oestrone to oestradiol was much more prominent than the reduction of androstenedione to testosterone by the polycystic tissue.

scholarly journals Effects of Organic Antagonists of Ca2+, Na+, and K+ on Chemotaxis and Motility ofEscherichia coli

2000 ◽  
Vol 182 (17) ◽  
pp. 4856-4861 ◽  
Author(s):  
Louis S. Tisa ◽  
Jeff J. Sekelsky ◽  
Julius Adler
Keyword(s):  
Escherichia Coli ◽  
Bacterial Chemotaxis ◽  
Animal Research ◽  
The Other ◽  
Ofescherichia Coli ◽  
Channel Blockers ◽  
Tetraethylammonium Chloride ◽  
E Coli ◽  
Other Hand ◽  
Nanomolar Range

ABSTRACT Various Ca2+ antagonists used in animal research, many of them known to be Ca2+ channel blockers, inhibitedEscherichia coli chemotaxis (measured as entry of cells into a capillary containing attractant). The most effective of these, acting in the nanomolar range, was ω-conotoxin GVIA. The next most effective were gallopamil and verapamil. At concentrations around 100-fold higher than that needed for inhibition of chemotaxis, each of these antagonists inhibited motility (measured as entry of cells into a capillary lacking attractant). Various other Ca2+antagonists were less effective, though chemotaxis was almost always more sensitive to inhibition than was motility. Cells treated with each of these Ca2+ antagonists swam with a running bias, i.e., tumbling was inhibited. Similarly, some Na+ antagonists used in animal research inhibited bacterial chemotaxis. E. coli chemotaxis was inhibited by saxitoxin at concentrations above 10−7 M, while more than 10−4 M was needed to inhibit motility. Cells treated with saxitoxin swam with a tumbling bias. In the case of other Na+ antagonists in animals, aconitine inhibited bacterial chemotaxis 10 times more effectively than it inhibited motility, and two others inhibited chemotaxis and motility at about the same concentration. In the case of K+ antagonists used in animal research, 4-aminopyridine blocked E. coli chemotaxis between 10−3 M and, totally, 10−2 M, while motility was not affected at 10−2 M; on the other hand, tetraethylammonium chloride failed to inhibit either chemotaxis or motility at 10−2 M.

scholarly journals Microsomal 20.ALPHA.-hydroxysteroid dehydrogenase activity for progesterone in human placenta.

1986 ◽  
Vol 33 (3) ◽  
pp. 361-368 ◽  
Author(s):  
TAKEO FUKUDA ◽  
KUMIKO HIRATO ◽  
TAKUMI YANAIHARA ◽  
TETSUYA NAKAYAMA
Keyword(s):  
Dehydrogenase Activity ◽  
Human Placenta ◽  
Hydroxysteroid Dehydrogenase

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.

Sign in / Sign up

Export Citation Format

Share Document