INCREASED RATIO OF 5α-REDUCTASE: 3α(β)-HYDROXYSTEROID DEHYDROGENASE ACTIVITIES IN THE HYPERPLASTIC HUMAN PROSTATE

1979 ◽  
Vol 80 (3) ◽  
pp. 289-301 ◽  
Author(s):  
NICHOLAS BRUCHOVSKY ◽  
GARY LIESKOVSKY
Keyword(s):  
Enzyme Activity ◽  
Dehydrogenase Activity ◽  
Reductase Activity ◽  
Hydroxysteroid Dehydrogenase ◽  
Normal Prostate ◽  
Tissue Protein ◽  
Abnormal Accumulation ◽  
Hyperplastic Tissue ◽  
The Mean ◽  
Generating System

The activities of 5α-reductase and 3α(β)-hydroxysteroid dehydrogenase were assayed in homogenates of eight normal, 21 hyperplastic and four carcinomatous human prostates. Samples consisting of 300–500 μg tissue protein in Tris buffer, pH 7·0, were incubated at 37 °C for 30 min in the presence of 50 nm-[3H]androgen and an NADPH-generating system started with 5 × 10−4 m-NADP. The yield of 5α- and 3α-reduced metabolites, as established by using t.l.c. and g.l.c., gave an estimate of enzyme activity. The formation of metabolites denoting 5α-reductase activity in normal, hyperplastic and carcinomatous tissue respectively was 28·8 ± 47 (s.e.m.), 76·8 ± 8·9 and 3·5 ± 0·7 pmol 30 min−1 mg protein−1; similarly, that denoting 3α(β)-hydroxysteroid dehydrogenase activity was 69·3 ± 6·7, 46·6 ± 5·7 and 38·8 ± 22·1 pmol 30 min−1 mg protein−1. In all normal prostates 5α-reductase activity was lower than 3α(β)-hydroxysteroid dehydrogenase activity. Conversely, in 18 out of 21 hyperplastic prostates, 5α-reductase activity was higher than 3α(β)-hydroxysteroid dehydrogenase activity. The effect of the increase in 5α-reductase activity without a compensatory change in 3α(β)-hydroxysteroid dehydrogenase activity was to alter the mean ratio between 5α-reductase and 3α(β)-hydroxysteroid dehydrogenase activities from 0·47 ± 0·11 in the normal prostate to 1·84 ± 0·19 in hyperplastic tissue. It is inferred that this change may predispose the hyperplastic prostate to asymmetrical rates of androgen metabolism and thereby contribute to the abnormal accumulation of dihydrotestosterone.

EFFECTS OF TAMOXIFEN ON THE BINDING AND METABOLISM OF TESTOSTERONE BY HUMAN PROSTATIC TISSUE AND PLASMA IN VITRO

1979 ◽  
Vol 83 (3) ◽  
pp. 369-378 ◽  
Author(s):  
F. K. HABIB ◽  
G. RAFATI ◽  
M. R. G. ROBINSON ◽  
S. R. STITCH
Keyword(s):  
Dehydrogenase Activity ◽  
Reductase Activity ◽  
Hydroxysteroid Dehydrogenase ◽  
Inhibitory Effect ◽  
Prostatic Tissue ◽  
Sex Hormone Binding Globulin ◽  
Benign Tissue ◽  
The Mean ◽  
Malignant Prostate

The in-vitro metabolism of testosterone in benign and malignant prostatic tissue was examined and distinct quantitative differences between the two types of specimens were observed. The major metabolite of testosterone in the hyperplastic prostate was 5α-dihydrotestosterone and a high 3α(β)-hydroxysteroid dehydrogenase activity was also detected. In the malignant tissue, 5α-reductase activity was considerably reduced and there was little or no androstanediol formed; the 17β-dehydrogenase activity was, however, higher than in the benign tissue. The decrease in 5α-reductase was always followed by a compensatory change in the 3α(β)-hydroxysteroid dehydrogenase of the malignant prostate. The present study revealed that the ratio of the mean activities of 5α-reductase to 3α(β)-hydroxysteroid dehydrogenase in the two types of specimen always remained a constant. Although the antioestrogen, tamoxifen, induced an inhibitory effect on the activities of 5α-reductase and 17β-hydroxysteroid dehydrogenase in the gland, the present investigation also suggested that tamoxifen stimulated the activity of 3α(3β)-hydroxysteroid dehydrogenase. In blood, the action of tamoxifen appeared to be confined to the displacement of androgens from the binding sites on the sex hormone binding globulin.

THE INFLUENCE OF HAEMOGLOBIN-S AND G6PD DEFICIENCY ON THE ACTIVITY OF THE 17β-HYDROXYSTEROID DEHYDROGENASE OF INTACT HUMAN ERYTHROCYTES

1974 ◽  
Vol 75 (4) ◽  
pp. 793-800
Author(s):  
A. O. Sogbesan ◽  
O. A. Dada ◽  
B. Kwaku Adadevoh
Keyword(s):  
Enzyme Activity ◽  
Dehydrogenase Activity ◽  
Sex Steroids ◽  
G6pd Deficiency ◽  
Incubation Medium ◽  
Hydroxysteroid Dehydrogenase ◽  
G6pd Activity ◽  
Reverse Transformation ◽  
Oxidative Transformation ◽  
Haemoglobin S

ABSTRACT The 17β-hydroxysteroid dehydrogenase activity in intact erythrocytes of Nigerian patients, in particular with regard to haemoglobin genotypes and G6PD* activity was studied. The G6PD activity of the erythrocyte did not affect the oxidative transformation of testosterone to androstenedione and of oestradiol to oestrone. The reduction (reverse transformation) was inhibited in G6PD-deficient erythrocytes but this inhibition was offset by the addition of 0.025 m glucose to the incubation medium. The per cent oxidation transformation of testosterone was higher in Hb-AA than in Hb-SS erythrocytes. It is suggested that the differences may be a result of either lower enzyme activity in the Hb-SS erythrocytes or of differences in the uptake and possibly binding of sex steroids by intact Hb-SS and Hb-AA erythrocytes.

'Liver-type' 11β-hydroxysteroid dehydrogenase cDNA encodes reductase but not dehydrogenase activity in intact mammalian COS-7 cells

1994 ◽  
Vol 13 (2) ◽  
pp. 167-174 ◽  
Author(s):  
S C Low ◽  
K E Chapman ◽  
C R W Edwards ◽  
J R Seckl
Keyword(s):  
Dehydrogenase Activity ◽  
Rat Liver ◽  
Mammalian Cells ◽  
Reductase Activity ◽  
Hydroxysteroid Dehydrogenase ◽  
Luciferase Reporter ◽  
Luciferase Expression ◽  
Intact Cells ◽  
Mmtv Ltr

ABSTRACT 11β-Hydroxysteroid dehydrogenase (11β-HSD) catalyses the metabolism of corticosterone to inert 11-dehydrocorticosterone, thus preventing glucocorticoid access to otherwise non-selective renal mineralocorticoid receptors (MRs), producing aldosterone selectivity in vivo. At least two isoforms of 11β-HSD exist. One isoform (11β-HSD1) has been purified from rat liver and an encoding cDNA cloned from a rat liver library. Transfection of rat 11β-HSD1 cDNA into amphibian cells with a mineralocorticoid phenotype encodes 11 β-reductase activity (activation of inert 11-dehydrocorticosterone) suggesting that 11β-HSD1 does not have the necessary properties to protect renal MRs from exposure to glucocorticoids. This function is likely to reside in a second 11β-HSD isoform. 11β-HSD1 is co-localized with glucocorticoid receptors (GRs) and may modulate glucocorticoid access to this receptor type. To examine the predominant direction of 11β-HSD1 activity in intact mammalian cells, and the possible role of 11β-HSD in regulating glucocorticoid access to GRs, we transfected rat 11β-HSD1 cDNA into a mammalian kidney-derived cell system (COS-7) which has little endogenous 11β-HSD activity or mRNA expression. Homogenates of COS-7 cells transfected with increasing amounts of 11β-HSD cDNA exhibited a dose-related increase in 11 β-dehydrogenase activity. In contrast, intact cells did not convert corticosterone to 11-dehydrocorticosterone over 24 h, but showed a clear dose-related 11β-reductase activity, apparent within 4 h of addition of 11-dehydrocorticosterone to the medium. To demonstrate that this reflected a change in functional intracellular glucocorticoids, COS-7 cells were co-transfected with an expression vector encoding GR and a glucocorticoid-inducible MMTV-LTR luciferase reporter construct, with or without 11β-HSD. Corticosterone induced MMTV-LTR luciferase expression in the presence or absence of 11β-HSD. 11-Dehydrocorticosterone was without activity in the absence of 11β-HSD, but induced MMTV-LTR luciferase activity in the presence of 11β-HSD. These results indicate that rat 11β-HSD1 can behave exclusively as a reductase in intact mammalian cells. Thus in some tissues in vivo, 11β-HSD1 may regulate ligand access to GRs by reactivating inert glucocorticoids.

ALTERATION OF 3β-HYDROXYSTEROID DEHYDROGENASE ACTIVITY IN RAT OVARIES DURING THE OESTROUS CYCLE

1974 ◽  
Vol 60 (3) ◽  
pp. 441-443 ◽  
Author(s):  
A. M. GAWIENOWSKI ◽  
J. N. CLARK ◽  
C. N. SRINIVASAN
Keyword(s):  
Enzyme Activity ◽  
Dehydrogenase Activity ◽  
Hydroxysteroid Dehydrogenase ◽  
Oestrous Cycle

SUMMARY The activity of 3β-hydroxysteroid dehydrogenase has been determined during various stages of the oestrous cycle in rats. The enzyme activity was high during pro-oestrus and oestrus but low during dioestrus I and II.

Corticosteroid receptors and 11β-hydroxysteroid dehydrogenase isoforms in rat intestinal epithelia

1999 ◽  
Vol 277 (3) ◽  
pp. G541-G547 ◽  
Author(s):  
Karen E. Sheppard ◽  
Kevin X. Z. Li ◽  
Dominic J. Autelitano
Keyword(s):  
Enzyme Activity ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cells ◽  
Reductase Activity ◽  
Distal Colon ◽  
Hydroxysteroid Dehydrogenase ◽  
Intestinal Epithelial ◽  
Rnase Protection ◽  
Intestinal Epithelia ◽  
Corticosteroid Receptors

To evaluate the potential roles that both receptors and enzymes play in corticosteroid regulation of intestinal function, we have determined glucocorticoid receptor (GR), mineralocorticoid receptor (MR), and 11β-hydroxysteroid dehydrogenase (11β-HSD) expression in intestinal epithelial cells. GR and MR mRNA and receptor binding were ubiquitously expressed in epithelial cells, with receptor levels higher in ileum and colon than jejunum and duodenum. RNase protection analysis showed that 11β-HSD1 was not expressed in intestinal epithelial cells, and enzyme activity studies detected no 11-reductase activity. 11β-HSD2 mRNA and protein were demonstrated in ileal and colonic epithelia; both MR and GR binding increased when enzyme activity was inhibited with carbenoxolone. Duodenal and jejunal epithelial cells showed very little 11β-HSD2 mRNA and undetectable 11β-HSD2 protein; despite minor (<7%) dehydrogenase activity in these cells, enzyme activity did not alter binding of corticosterone to either MR or GR. These findings demonstrate the ubiquitous but differential expression of MR and GR in intestinal epithelia and that 11β-HSD2 modulates corticosteroid binding to both MR and GR in ileum and proximal and distal colon but not in duodenum or jejunum.

scholarly journals A HISTOCHEMICAL METHOD FOR THE DEMONSTRATION OF 20α-HYDROXYSTEROID DEHYDROGENASE ACTIVITY IN RAT OVARIES

1964 ◽  
Vol 12 (9) ◽  
pp. 670-673 ◽  
Author(s):  
KÁROLY BALOGH
Keyword(s):  
Enzyme Activity ◽  
Corpus Luteum ◽  
Dehydrogenase Activity ◽  
Present Method ◽  
Hydroxysteroid Dehydrogenase ◽  
Microscopic Level ◽  
Corpora Lutea ◽  
Endocrine Glands ◽  
Progesterone Metabolism ◽  
Rat Ovary

20α-Hydroxysteroid dehydrogenase activity was localized histochemically in the corpus luteum of the rat by using Nitro-BT as an indicator. Intensive enzyme activity was obseryed in the corpus luteum cells, especially during involution. The placenta and corpora lutea of pregnancy failed to reveal enzyme activity during the last week of gravidity. Other tissues, including endocrine glands, liver and kidneys were also negative. The Present method offers a possibility to identify the sites of progesterone metabolism in the rat ovary at the microscopic level.

Purification and Properties of the Soluble 17β-Hydroxysteroid Dehydrogenase of Rabbit Uterus

1979 ◽  
Vol 34 (9-10) ◽  
pp. 726-737 ◽  
Author(s):  
Kunhard Pollow ◽  
Walter Eiger ◽  
Herrmann Heßlinger ◽  
Barbara Pollow
Keyword(s):  
Enzyme Activity ◽  
Dehydrogenase Activity ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Hydroxysteroid Dehydrogenase ◽  
Maximal Velocity ◽  
Ammonium Sulfate Precipitation ◽  
Ph Optimum ◽  
Mobility Data ◽  
Purification And Properties

Abstract 17 β-Hydroxysteroid dehydrogenase activity towards estradiol-17 β has been demonstrated in the 105,000 X g supernatant of rabbit uterus. Hydroxylapatite chromatography of the enzyme activity isolated by ammonium sulfate precipitation, gel filtration and DEAE-cellulose chromato­graphy yielded a single 17 β-hydroxysteroid dehydrogenase activity. Further purification of the enzyme preparation by isoelectric focusing resulted in multiple peaks of activity. The molecular weight or the enzyme, calculated from mobility data on Sephadex gel, is approximately 64,000. Some properties of partially purified 17 β-hydroxysteroid dehydrogenase activity have been studied. Estradiol-17 β reacts at a faster rate than testosterone. The Km for estradiol is 4.16X 10-5 mol/1 for the NAD-linked enzyme activity and 4.37 X 10-5 mol/1 when NADP as cofactor was used. The ratio of the maximal velocity for NADP to that for NAD was 1.42. The pH-optimum for estradiol appears between 9.5 and 10.5 and for estrone between 5.5 and 6.5. The enzyme appears to be of the sulfhydryl type.

Effects of unilateral orchidectomy on rat epididymal Δ4-5α-reductase and 3α-hydroxysteroid dehydrogenase

1979 ◽  
Vol 57 (9) ◽  
pp. 998-1003 ◽  
Author(s):  
B. Robaire
Keyword(s):  
Luteinizing Hormone ◽  
Dehydrogenase Activity ◽  
Reductase Activity ◽  
Follicle Stimulating Hormone ◽  
Hydroxysteroid Dehydrogenase ◽  
Peripheral Circulation ◽  
Seminal Vesicles ◽  
Ventral Prostate ◽  
Metabolizing Enzymes ◽  
Adult Rat

The effects of unilateral orchidectomy on the adult rat epididymal testosterone metabolizing enzymes, Δ4-5α-reductase and α-hydroxysteroid dehydrogenase, are investigated. Five weeks following unilateral orchidectomy, it is found that the activity of 3α-hydroxysteroid dehydrogenase per organ is not altered, whereas Δ4-5α-reductase activity decreased by more than 80% on the side of the orchidectomy. Neither accessory sex tissue weights, ventral prostate and seminal vesicles, nor the concentration of circulating testosterone, luteinizing hormone, follicle-stimulating hormone, or prolactin is altered by unilateral orchidectomy. These data indicate that (1) epididymal 3α-hydroxysteroid dehydrogenase activity can be maintained by circulating androgens and that (2) the major factor regulating Δ4-5α-reductase activity is not a substance secreted by the testes into the peripheral circulation. It is suggested that a substance directly secreted into the epididymis by the testis regulates epididymal Δ4-5α-reductase activity.

scholarly journals Hexose-6-phosphate dehydrogenase confers oxo-reductase activity upon 11β-hydroxysteroid dehydrogenase type 1

2005 ◽  
Vol 34 (3) ◽  
pp. 675-684 ◽  
Author(s):  
Iwona J Bujalska ◽  
Nicole Draper ◽  
Zoi Michailidou ◽  
Jeremy W Tomlinson ◽  
Perrin C White ◽  
...  
Keyword(s):  
Dehydrogenase Activity ◽  
Reductase Activity ◽  
Chinese Hamster ◽  
Hydroxysteroid Dehydrogenase ◽  
Mrna Levels ◽  
Gene Encoding ◽  
Intact Cells ◽  
Hek 293 ◽  
Treatment Of Obesity ◽  
Novel Target

Two isozymes of 11β-hydroxysteroid dehydrogenase (11β-HSD) interconvert active cortisol and inactive cortisone. 11β-HSD2 (renal) acts only as a dehydrogenase, converting cortisol to cortisone. 11β-HSD1 (liver) is a bi-directional enzyme in cell homogenates, whereas in intact cells it typically displays oxo-reductase activity, generating cortisol from cortisone. We recently established that cortisone reductase deficiency is a digenic disease requiring mutations in both the gene encoding 11β-HSD1 and in the gene for a novel enzyme located within the lumen of the endoplasmic reticulum (ER), hexose-6-phosphate dehydrogenase (H6PDH). This latter enzyme generates NADPH, the co-factor required for oxo-reductase activity. Therefore, we hypothesized that H6PDH expression may be an important determinant of 11β-HSD1 oxo-reductase activity. Transient transfection of chinese hamster ovary (CHO) cells with 11β-HSD1 resulted in the appearance of both oxo-reductase and dehydrogenase activities in intact cells. Co-transfection of 11β-HSD1 with H6PDH increased oxo-reductase activity whilst virtually eliminating dehydrogenase activity. In contrast, H6PDH had no effect on reaction direction of 11β-HSD2, nor did the cytosolic enzyme, glucose-6-phosphate dehydrogenase (G6PD) affect 11β-HSD1 oxo-reductase activity. Conversely in HEK 293 cells stably transfected with 11β-HSD1 cDNA, transfection of an H6PDH siRNA reduced 11β-HSD1 oxo-reductase activity whilst simultaneously increasing 11β-HSD1 dehydrogenase activity. In human omental preadipocytes obtained from 15 females of variable body mass index (BMI), H6PDH mRNA levels positively correlated with 11β-HSD1 oxo-reductase activity, independent of 11β-HSD1 mRNA levels. H6PDH expression increased 5.3-fold across adipocyte differentiation (P<0.05) and was associated with a switch from 11β-HSD1 dehydrogenase to oxo-reductase activity. In conclusion, H6PDH is a crucial determinant of 11β-HSD1 oxo-reductase activity in intact cells. Through its interaction with 11β-HSD1, H6PDH may represent a novel target in the pathogenesis and treatment of obesity.

scholarly journals A Switch in Dehydrogenase to Reductase Activity of 11β-Hydroxysteroid Dehydrogenase Type 1 upon Differentiation of Human Omental Adipose Stromal Cells

2002 ◽  
Vol 87 (3) ◽  
pp. 1205-1210 ◽  
Author(s):  
Iwona J. Bujalska ◽  
Elizabeth A. Walker ◽  
Martin Hewison ◽  
Paul M. Stewart
Keyword(s):  
Dehydrogenase Activity ◽  
Lipoprotein Lipase ◽  
Stromal Cells ◽  
Adipocyte Differentiation ◽  
Reductase Activity ◽  
Hydroxysteroid Dehydrogenase ◽  
Mrna Levels ◽  
Adipose Stromal Cells ◽  
Glycerol 3 Phosphate Dehydrogenase

As exemplified in patients with Cushing’s syndrome, glucocorticoids play an important role in regulating adipose tissue distribution and function, but circulating cortisol concentrations are normal in most patients with obesity. However, human omental adipose stromal cells (ASCs) can generate glucocorticoid locally through the expression of the enzyme 11β-hydroxysteroid dehydrogenase (11β-HSD) type 1 (11β-HSD1), which, in intact cells, has been considered to be an oxoreductase, converting inactive cortisone (E) to cortisol (F). Locally produced F can induce ASC differentiation, but the relationship between 11β-HSD1 expression and adipocyte differentiation is unknown. Primary cultures of paired omental (om) and sc ASC and adipocytes were prepared from 17 patients undergoing elective abdominal surgery and cultured for up to 14 d. Expression and activity of 11β-HSD isozymes were analyzed together with early (lipoprotein lipase) and terminal (glycerol 3 phosphate dehydrogenase) markers of adipocyte differentiation. On d 1 of culture, 11β-HSD1 activity in intact om ASCs exceeded oxoreductase activity in every patient (78.9 ± 24.9 vs. 15.8 ± 3.7 [mean ± se] pmol/mg per hour, P &lt; 0.001), and in sc ASCs, relative activities were similar (40.6 ± 12.2 vs. 36.9 ± 8.8). Conversely, in freshly isolated om adipocytes, reductase activity exceeded dehydrogenase activity (23.6 ± 1.5 vs. 6.2 ± 0.8 pmol/mg per hour, P &lt; 0.01). Following 14 d of culture in serum-free conditions with addition of 10 nm insulin (Ctr) or insulin with 100 nm F (+F), lipoprotein lipase/18S RNA levels increased in both the Ctr- and +F-treated ASCs, but glycerol 3 phosphate dehydrogenase increased only in the +F cultures. In both cases, however, 11β-HSD1 oxoreductase activity exceeded dehydrogenase activity (Ctr: 53.3 ± 9.0 vs. 32.4 ± 10.5, P &lt; 0.05; +F: 65.6 ± 15.6 vs. 37.1 ± 11.5 pmol/mg per hour, P &lt; 0.05), despite no significant changes in 11β-HSD1 mRNA levels. In sc ASCs, dehydrogenase activity was similar to reductase activity in both Ctr- and +F-treated cells. Type 2 11β-HSD expression was undetectable in each case. These data show that in intact, undifferentiated om ASCs, 11β-HSD1 acts primarily as a dehydrogenase, but in mature adipocytes oxoreductase activity predominates. Because glucocorticoids inhibit cell proliferation, we postulate that 11β-HSD1 activity in uncommitted ASCs may facilitate proliferation rather than differentiation. Once early differentiation is initiated, a “switch” to 11β-HSD1 oxoreductase activity generates F, thus promoting adipogenesis. Site-specific regulation of the set-point of 11β-HSD1 activity may be an important mechanism underpinning visceral obesity.

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