METABOLISM OF ANDROGENS IN VITRO BY HUMAN FOETAL SKIN

1976 ◽  
Vol 70 (3) ◽  
pp. 491-499 ◽  
Author(s):  
F. SHARP ◽  
J. B. HAY ◽  
M. B. HODGINS
Keyword(s):  
Gestational Age ◽  
Enzyme Activities ◽  
Histochemical Study ◽  
Reductase Activity ◽  
Hydroxysteroid Dehydrogenase ◽  
Sebaceous Glands ◽  
Isomerase Activity ◽  
Human Foetuses

SUMMARY Fresh scalp, genital, chest and axillary skin from human foetuses of 12–41 weeks' maturity was incubated in Krebs' improved Ringer I medium with [7α-3H]dehydroepiandrosterone, [7α-3H]testosterone and [7α-3H]androstenedione. The metabolites identified were androstenedione, 5α-androstane-3,17-dione, androsterone, 3-epiandrosterone, 5α-dihydrotestosterone, 5α-androstane-3α,17β-diol, 5α-androstane-3β,17β-diol, 5-androstene-3β,17β-diol and testosterone. The results provide evidence for the presence of 3β-hydroxysteroid dehydrogenase, Δ4–5 isomerase, 17β-hydroxysteroid dehydrogenase, Δ4-3-oxosteroid-5α-reductase and 3α-hydroxysteroid dehydrogenase in human foetal skin. There were quantitative differences in the various enzyme activities between different body sites and skin specimens of different gestational age. 5α-Reductase activity was particularly high in genital skin. 3β-Hydroxysteroid dehydrogenase Δ4–5 isomerase activity was low in skin from a 12-week foetus, but high in skin specimens from 28-, 38- and 41-week foetuses. 17β-Hydroxysteroid dehydrogenase activity was already high in the skin of the 12-week foetus and remained so in the older foetuses. These results were correlated with the development of the foetal sebaceous glands, and were in general agreement with a parallel enzyme histochemical study. The role of androgen metabolism in human foetal skin is discussed.

STEROID METABOLISM IN KIDNEY TISSUE

1972 ◽  
Vol 71 (3) ◽  
pp. 530-538 ◽  
Author(s):  
I. Huhtaniemi ◽  
R. Vihko
Keyword(s):  
Gestational Age ◽  
Enzyme Activities ◽  
Kidney Tissue ◽  
Steroid Metabolism ◽  
Foetal Kidney

ABSTRACT The endogenous neutral steroids in early and mid-term (gestational age 10-14 weeks) human foetal kidneys were investigated. Fractions of unconjugated and mono- and disulphated neutral steroids were studied separately. No unconjugated compounds were detected, but the following steroid monosulphates were found: dehydroepiandrosterone, 5-androstene3β,17α-diol, 5-androstene-3β,17β-diol, 16α-hydroxydehydroepiandrosterone, 16β-hydroxydehydroepiandrosterone, 3β,17β-dihydroxy-5-androsten-16-one, pregnenolone, 5-pregnene-3β,20α-diol, 16α-hydroxypregnenolone and 17α-hydroxypregnenolone. In addition, the following compounds were present, as disulphates: 5-androstene-3β,17α-diol, 5-androstene-3β,17β-diol and 5-pregnene-3β,20α-diol. Quantitatively, dehydroepiandrosterone, 16α-hydroxydehydroepiandrosterone and pregnenolone in the monosulphate fraction and 5-androstene-3β,17α-diol in the disulphate fraction were the main steroids found. Furthermore, in vitro incubations with minced or homogenized foetal kidney tissue demonstrated the following enzyme activities: 16α-hydroxylase, 17β-reductase, 20α-reductase and sulphokinase. In the incubations, dehydroepiandrosterone, pregnenolone and their sulphate conjugates were used as substrates. The role of the foetal kidneys in the metabolism of neutral steroids during early and mid-pregnancy is discussed.

Premature Adrenarche in Girls Characterized By Enhanced 17,20-Lyase and 17β-Hydroxysteroid Dehydrogenase Activities

2020 ◽  
Vol 105 (12) ◽  
pp. e4439-e4451
Author(s):  
Marco Janner ◽  
Grit Sommer ◽  
Michael Groessl ◽  
Christa E Flück
Keyword(s):  
Enzyme Activities ◽  
Prospective Observational Study ◽  
Polycystic Ovary ◽  
Reductase Activity ◽  
Hydroxysteroid Dehydrogenase ◽  
Pediatric Endocrinology ◽  
Ovary Syndrome ◽  
Premature Adrenarche ◽  
Urinary Steroid

Abstract Context Girls with premature adrenarche (PA) may have a higher risk of developing polycystic ovary syndrome (PCOS) and metabolic syndrome. The biological purpose of adrenarche is unknown and the role of novel biosynthetic pathways remains unclear. Objective To compare the urinary steroid metabolome and enzyme activities of girls with PA to age-matched control girls and to published steroid values of girls with normal adrenarche and of women with PCOS and their newborn daughters. Design Prospective observational study from 2009 to 2014. Setting Academic pediatric endocrinology referral center. Participants Twenty-three girls with PA and 22 healthy, age-matched girls. Main Outcome Measures Steroid metabolites in 24-hour urine samples, including 4 progesterones, 5 corticosterones, aldosterone, 13 androgens, 2 estrogens, 14 glucocorticoids, and enzyme activities represented by metabolite ratios. Results Girls with PA had a higher body mass index (mean standard deviation scores 0.9 vs -0.3, P = 0.013). Androgen excretion was higher in PA girls than in control girls (median 3257 nmol/24 hours vs 1627 nmol/24 hours, P < 0.001), in particular metabolites from alternate androgen pathways. The amount of progesterone, corticosterone, aldosterone, estrogen, and cortisol metabolites were similar between groups. Activities of 17β-hydroxysteroid-dehydrogenase and of 17,20-lyase were higher in girls with PA. Activities of 3β-hydroxysteroid-dehydrogenase, 21-hydroxylase, and 5α-reductase activity were not different between groups, in contrast to published results on girls with normal adrenarche or PCOS females. Conclusions Metabolites and enzymes involved in alternate androgen pathways appear to be markers of PA. Prospective studies should assess whether steroid production in PA also differs from adrenarche at normal timing and persists into adulthood.

HYPOTHALAMIC, PITUITARY AND TESTICULAR FUNCTION DURING SEXUAL MATURATION OF THE MALE RAT

1977 ◽  
Vol 72 (1) ◽  
pp. 17-26 ◽  
Author(s):  
A. H. PAYNE ◽  
R. P. KELCH ◽  
E. P. MURONO ◽  
J. T. KERLAN
Keyword(s):  
Dehydrogenase Activity ◽  
Sexual Maturation ◽  
Hydroxysteroid Dehydrogenase ◽  
Male Rat ◽  
Releasing Hormone ◽  
Isomerase Activity ◽  
Serum Lh ◽  
Rate Of Increase ◽  
Gonadotrophin Releasing Hormone

SUMMARY Hypothalamic content of gonadotrophin-releasing hormone (GnRH), serum LH and FSH, capacity of the testis to synthesize testosterone in vitro, and testicular 5-ene-3β-hydroxysteroid dehydrogenase-isomerase and 17β-hydroxysteroid dehydrogenase were measured in groups of rats at approximately 5 day intervals from birth to day 64 and at days 74 and 89. The capacity of the testes to synthesize testosterone in vitro was measured in the presence of a saturating dose of rat LH. Gonadotrophin-releasing hormone increased steadily from 0·17 ng per hypothalamus at birth to a maximum of 7 ng at day 52 and then remained constant. LH concentrations were highly variable and often exceeded adult values between days 10 and 32. After day 32 a steady rise was observed which reached adult values between days 37 and 42. FSH concentrations markedly increased from 255 ng/ml observed at birth and day 10 to a peak value of 1000 ng/ml at day 32. Subsequently there was a steady decline in FSH values until day 74 when the concentration returned to values found at birth. 5-ene-3β-Hydroxysteroid dehydrogenase-isomerase activity exhibited a rapid increase between days 12 and 19 followed by an even greater rate of increase between days 19 and 32 when adult levels were attained. 17β-Hydroxysteroid dehydrogenase activity was very low between birth and day 22. Enzyme activity began to increase at day 22 with a rapid increase in activity observed between days 37 and 58. The increase in capacity to synthesize testosterone closely followed the increase in 17β-hydroxysteroid dehydrogenase activity. The study demonstrates that during sexual maturation in the male rat, changes in serum LH and FSH do not reflect changes in hypothalamic GnRH. The appearance of Leydig cells as monitored by 5-ene-3β-hydroxysteroid dehydrogenase-isomerase activity precedes by approximately 20 days the increase in testicular capacity to synthesize testosterone in vitro. The latter coincides with the increase in 17β-hydroxysteroid dehydrogenase activity. These results suggest that 17β-hydroxysteroid dehydrogenase is a limiting factor in the ability of the testis to respond to LH stimulation.

Intracellular regulation of 17β-hydroxysteroid dehydrogenase type 2 catalytic activity in A431 cells

1997 ◽  
Vol 153 (3) ◽  
pp. 453-464 ◽  
Author(s):  
C H Blomquist ◽  
B S Leung ◽  
C Beaudoin ◽  
D Poirier ◽  
Y Tremblay
Keyword(s):  
Reductase Activity ◽  
Maximum Velocity ◽  
Hydroxysteroid Dehydrogenase ◽  
A431 Cells ◽  
Intact Cells ◽  
Cell Monolayers ◽  
Intracellular Regulation

Abstract There is growing evidence that various isoforms of 17β-hydroxysteroid dehydrogenase (17-HSD) are regulated at the level of catalysis in intact cells. A number of investigators have proposed that the NAD(P)/NAD(P)H ratio may control the direction of reaction. In a previous study, we obtained evidence that A431 cells, derived from an epidermoid carcinoma of the vulva, are enriched in 17-HSD type 2, a membrane-bound isoform reactive with C18 and C19 17β-hydroxysteroids and 17-ketosteroids. The present investigation was undertaken to confirm the presence of 17-HSD type 2 in A431 cells and to assess intracellular regulation of 17-HSD at the level of catalysis by comparing the activity of homogenates and microsomes with that of cell monolayers. Northern blot analysis confirmed the presence of 17-HSD type 2 mRNA. Exposure of cells to epidermal growth factor resulted in an increase in type 2 mRNA and, for microsomes, increases in maximum velocity (Vmax) with no change in Michaelis constant (Km) for testosterone and androstenedione, resulting in equivalent increases in the Vmax/Km ratio consistent with the presence of a single enzyme. Initial velocity data and inhibition patterns were consistent with a highly ordered reaction sequence in vitro in which testosterone and androstenedione bind only to either an enzyme–NAD or an enzyme–NADH complex respectively. Microsomal dehydrogenase activity with testosterone was 2- to 3-fold higher than reductase activity with androstenedione. In contrast, although cell monolayers rapidly converted testosterone to androstenedione, reductase activity with androstenedione or dehydroepiandrosterone (DHEA) was barely detectable. Lactate but not glucose, pyruvate or isocitrate stimulated the conversion of androstenedione to testosterone by monolayers, suggesting that cytoplasmic NADH may be the cofactor for 17-HSD type 2 reductase activity with androstenedione. However, exposure to lactate did not result in a significant change in the NAD/NADH ratio of cell monolayers. It appears that within A431 cells 17-HSD type 2 is regulated at the level of catalysis to function almost exclusively as a dehydrogenase. These findings give further support to the concept that 17-HSD type 2 functions in vivo principally as a dehydrogenase and that its role as a reductase in testosterone formation by either the Δ4 or Δ5 pathway is limited. Journal of Endocrinology (1997) 153, 453–464

scholarly journals Inactivation of glucocorticoids by 11β-hydroxysteroid dehydrogenase enzymes increases during the meiotic maturation of porcine oocytes

Reproduction ◽  
2008 ◽  
Vol 136 (6) ◽  
pp. 725-732 ◽  
Author(s):  
Rachel J Webb ◽  
Neera Sunak ◽  
Lisa Wren ◽  
Anthony E Michael
Keyword(s):  
Oocyte Maturation ◽  
Enzyme Activities ◽  
Germinal Vesicle ◽  
Hydroxysteroid Dehydrogenase ◽  
Target Cells ◽  
Cortisol Metabolism ◽  
Enzymatic Inactivation ◽  
Glucocorticoid Metabolism ◽  
Ovarian Cyst Fluid

Recent reports have shown that glucocorticoids can modulate oocyte maturation in both teleost fish and mammals. Within potential target cells, the actions of physiological glucocorticoids are modulated by 11β-hydroxysteroid dehydrogenase (HSD11B) isoenzymes that catalyse the interconversion of cortisol and cortisone. Hence, the objective of this study was to establish whether HSD11B enzymes mediate cortisol–cortisone metabolism in porcine oocytes and, if so, whether the rate of glucocorticoid metabolism changes during oocyte maturation. Enzyme activities were measured in cumulus–oocyte complexes (COCs) and denuded oocytes (DOs) using radiometric conversion assays. While COCs and DOs oxidised cortisol to inert cortisone, there was no detectable regeneration of cortisol from cortisone. The rate of cortisol oxidation was higher in expanded COCs than in compact COCs containing germinal vesicle (GV) stage oocytes (111±6 vs 2041±115 fmol cortisone/oocyte.24 h; P<0.001). Likewise, HSD11B activities were 17±1 fold higher in DOs from expanded COCs than in those from compact COCs (P<0.001). When GV stage oocytes were subject to a 48 h in vitro maturation protocol, the enzyme activities were significantly increased from 146±18 to 1857±276 fmol cortisone/oocyte.24 h in GV versus MII stage oocytes respectively (P<0.001). Cortisol metabolism was inhibited by established pharmacological inhibitors of HSD11B (glycyrrhetinic acid and carbenoxolone), and by porcine follicular and ovarian cyst fluid. We conclude that an HSD11B enzyme (or enzymes) functions within porcine oocytes to oxidise cortisol, and that this enzymatic inactivation of cortisol increases during oocyte maturation.

scholarly journals Modulation of 11β-Hydroxysteroid Dehydrogenase Isozymes by Growth Hormone and Insulin-Like Growth Factor: In Vivo and In Vitro Studies1

1999 ◽  
Vol 84 (11) ◽  
pp. 4172-4177 ◽  
Author(s):  
J. S. Moore ◽  
J. P. Monson ◽  
G. Kaltsas ◽  
P. Putignano ◽  
P. J. Wood ◽  
...  
Keyword(s):  
Growth Factor ◽  
Reductase Activity ◽  
Primary Cultures ◽  
Inverse Correlation ◽  
Hydroxysteroid Dehydrogenase ◽  
Insulin Like Growth Factor ◽  
Igf I ◽  
Glucose Output

The interconversion of hormonally active cortisol (F) and inactive cortisone (E) is catalyzed by two isozymes of 11β-hydroxysteroid dehydrogenase (11βHSD), an oxo-reductase converting E to F (11βHSD1) and a dehydrogenase (11βHSD2) converting F to E. 11βHSD1 is important in mediating glucocorticoid-regulated glucose homeostasis and regional adipocyte differentiation. Earlier studies conducted with GH-deficient subjects treated with replacement GH suggested that GH may modulate 11βHSD1 activity. In 7 acromegalic subjects withdrawing from medical therapy (Sandostatin-LAR; 20–40 mg/month for at least 12 months), GH rose from 7.1 ± 1.5 to 17.5 ± 4.3 mU/L (mean ± se), and insulin-like growth factor I (IGF-I) rose from 43.0 ± 8.8 to 82.1 ± 13.7 nmol/L (both P &lt; 0.05) 4 months after treatment. There was a significant alteration in the normal set-point of F to E interconversion toward E. The fall in the urinary tetrahydrocortisols/tetrahydocortisone ratio (THF+allo-THF/THE; 0.82 ± 0.06 to 0.60 ± 0.06; P &lt; 0.02) but unaltered urinary free F/urinary free E ratio (a marker for 11βHSD2 activity) suggested that this was due to inhibition of 11βHSD1 activity. An inverse correlation between GH and the THF+allo-THF/THE ratio was observed (r = −0.422; P &lt; 0.05). Conversely, in 12 acromegalic patients treated by transsphenoidal surgery (GH falling from 124 ± 49.2 to 29.3 ± 15.4 mU/L; P &lt; 0.01), the THF+allo-THF/THE ratio rose from 0.53 ± 0.06 to 0.63 ± 0.07 (P &lt; 0.05). Patients from either group who failed to demonstrate a change in GH levels showed no change in the THF+allo-THF/THE ratio. In vitro studies conducted on cells stably transfected with either the human 11βHSD1 or 11βHSD2 complementary DNA and primary cultures of human omental adipose stromal cells expressing only the 11βHSD1 isozyme indicated a dose-dependent inhibition of 11βHSD1 oxo-reductase activity with IGF-I, but not GH. Neither IGF-I nor GH had any effect on 11βHSD2 activity. GH, through an IGF-I-mediated effect, inhibits 11βHSD1 activity. This reduction in E to F conversion will increase the MCR of F, and care should be taken to monitor the adequacy of function of the hypothalamo-pituitary-adrenal axis in acromegalic subjects and in GH-deficient, hypopituitary patients commencing replacement GH therapy. Conversely, enhanced E to F conversion occurs with a reduction in GH levels; in liver and adipose tissue this would result in increased hepatic glucose output and visceral adiposity, suggesting that part of the phenotype currently attributable to adult GH deficiency may be an indirect consequence of its effect on tissue F metabolism via 11βHSD1 expression.

Detection of protein disulphide-isomerase in sheep pancreas fractions

1982 ◽  
Vol 2 (5) ◽  
pp. 343-349 ◽  
Author(s):  
David A. Hillson ◽  
Jacqueline Anderson
Keyword(s):  
Specific Activity ◽  
Protein Biosynthesis ◽  
Major Site ◽  
General Role ◽  
Protein Disulphide Isomerase ◽  
Isomerase Activity ◽  
Liver Homogenates ◽  
Specific Activities

Conclusions The use of diethylpyrocarbonate to inhibit endogenous ribonuclease in sheep pancreas allows the detection of protein-disulphide-isomerase activity in homogenates, at specific activities of up to 4 units/g. This is higher than the specific activity in sheep liver homogenates (about 2 units/g) or in homogenates of other sheep tissues (16). It is thus evident that high levels of protein-disulphide-isomerase activity are present in sheep pancreas. This is consistent both with the postulated general role of protein disulphide-isomerase in protein biosynthesis (10,11) and with the in vitro action of the enzyme on its conventional substrate scrambled ribonuclease, since pancreas is the major site of ribonuclease synthesis.

ENDOGENOUS NEUTRAL STEROIDS IN THE LUNG TISSUE OF EARLY AND MID-TERM HUMAN FOETUSES AND IN VITRO STUDIES ON THEIR FORMATION

1974 ◽  
Vol 75 (1) ◽  
pp. 148-158 ◽  
Author(s):  
I. Huhtaniemi
Keyword(s):  
Mass Spectrometry ◽  
Lung Tissue ◽  
Hydroxysteroid Dehydrogenase ◽  
Gas Liquid Chromatography ◽  
Wet Weight ◽  
Total Concentrations ◽  
Insight Into ◽  
Human Foetuses ◽  
Endogenous Steroids

ABSTRACT Four pools of lung tissue from 2 or 3 foetuses of 11–17 weeks' gestational age were analyzed by gas-liquid chromatography and gaschromatography-mass spectrometry for endogenous neutral steroids. All of the steroids detected were present as their mono- or disulphate conjugates. No free compounds were found. Dehydroepiandrosterone, pregnenolone and their 16α-hydroxylated derivatives were the compounds present in highest concentrations in the monosulphate fraction. The most prominent steroid in the disulphate fraction was 5-androstene-3β,17α-diol. Other compounds detected were the monosulphates of 3β,7α-dihydroxy-5-androsten-17-one, 3β,16β- dihydroxy -5- androsten-17-one, 3β,17β- dihydroxy-5-androsten-16-one, 5-androstene-3β,16β,1 7α-triol, 5-pregnene-3β,17α-diol, and 3β,17α-dihydroxy-5-pregnen-20-one and the disulphates of 5-androstene-3β,17β-diol, 3β,16α-dihydroxy-5-androsten-17-one and 5-pregnene-3β,20α-diol. The total concentrations of steroids in the lung tissue varied from 300 to 600 μg/100 g tissue wet weight. In order to gain some insight into the origin of the endogenous steroids detected, i. e. whether they were synthesized by the lung tissue or only filtered by it from the perfusing blood, minced lung tissue was incubated with dehydroepiandrosterone, pregnenolone, 3β,17α-dihydroxy-5-pregnen-20-one and with their sulphate conjugates. Evidence for the presence of the following enzymes was found: sulphokinase, 7α-hydroxylase, 16αhydroxylase, 17α-hydroxylase, 17β-hydroxysteroid dehydrogenase, 20α-hydroxysteroid dehydrogenase and C17–20 desmolase.

Enzyme-Activities Associated With Salivary-Glands of the Froghopper Eoscarta-Carnifex (F) (Homoptera, Cercopoidae) - Possible Role of Salivary Catalase in Phytotoxicity

1992 ◽  
Vol 40 (4) ◽  
pp. 365 ◽  
Author(s):  
DH Rodman ◽  
DJ Miller
Keyword(s):  
Salivary Glands ◽  
Enzyme Activities ◽  
New World ◽  
Yield Losses ◽  
Injury Response ◽  
Plant Peroxidase ◽  
Major Injury ◽  
Plant Injury

'Froghopper blight', systemic damage caused by an unidentified toxin in the saliva of various homopterans (superfamily Cercopoidea), is responsible for massive yield losses in many sugarcane-growing areas of the New World. The nature of the toxin remains unclear. In addition to lipases and several glycosidases, extracts of salivary glands of the Australian froghopper Eoscarta carnifex (F.) were found to contain high levels of catalase. The insect catalase was shown to inhibit plant peroxidase in vitro; peroxidases are induced by wounding and are central to many of the major injury responses of the plant. We hypothesise that the role of the salivary catalase in E. carnifex may be in scavenging peroxide, thus suppressing the plant injury response.

Sign in / Sign up

Export Citation Format

Share Document