Cloning of rat 17 beta-hydroxysteroid dehydrogenase type 2 and characterization of tissue distribution and catalytic activity of rat type 1 and type 2 enzymes.

Western blot analyses of various hamster tissues reveal high levels of expression of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) in adrenal and liver, and moderate levels of expression in kidney. The expression in liver is sexually dimorphic; very high levels of protein are observed in adult male liver but very low levels are seen in the female liver. Three distinct cDNAs encoding isoforms of 3 beta-HSD were isolated from hamster cDNA libraries. The type 1 isoform is a high-affinity dehydrogenase/isomerase expressed in adrenal and male kidney. The type 2 isoform is also a high-affinity dehydrogenase/isomerase expressed in kidney and male liver. The type 3 enzyme is a 3-ketosteroid reductase expressed predominantly in kidney. Sequencing of the clones showed that all three are structurally very similar, although types 1 and 2 share the greatest degree of similarity. Immunohistochemical staining for 3 beta-HSD in the adrenal was found throughout the adrenal cortex. In the kidney staining was confined to tubules, and in the liver, heavy staining was found in hepatocytes. The cloning of cDNAs for 3 beta-HSD from the liver and kidney should help in elucidating the function of this enzyme in these tissues.

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Human 3α-hydroxysteroid dehydrogenase isoforms (AKR1C1–AKR1C4) of the aldo-keto reductase superfamily: functional plasticity and tissue distribution reveals roles in the inactivation and formation of male and female sex hormones

Biochemical Journal ◽

10.1042/bj3510067 ◽

2000 ◽

Vol 351 (1) ◽

pp. 67-77 ◽

Cited By ~ 17

Author(s):

Trevor M. PENNING ◽

Michael E. BURCZYNSKI ◽

Joseph M. JEZ ◽

Chien-Fu HUNG ◽

Hseuh-Kung LIN ◽

...

Keyword(s):

Tissue Distribution ◽

Hydroxysteroid Dehydrogenase ◽

Reaction Products ◽

Functional Plasticity ◽

Dominant Form ◽

Female Sex Hormones ◽

Steroid Substrate ◽

Type 3

The kinetic parameters, steroid substrate specificity and identities of reaction products were determined for four homogeneous recombinant human 3α-hydroxysteroid dehydrogenase (3α-HSD) isoforms of the aldo-keto reductase (AKR) superfamily. The enzymes correspond to type 1 3α-HSD (AKR1C4), type 2 3α(17β)-HSD (AKR1C3), type 3 3α-HSD (AKR1C2) and 20α(3α)-HSD (AKR1C1), and share at least 84% amino acid sequence identity. All enzymes acted as NAD(P)(H)-dependent 3-, 17- and 20-ketosteroid reductases and as 3α-, 17β- and 20α-hydroxysteroid oxidases. The functional plasticity of these isoforms highlights their ability to modulate the levels of active androgens, oestrogens and progestins. Salient features were that AKR1C4 was the most catalytically efficient, with kcat/Km values for substrates that exceeded those obtained with other isoforms by 10–30-fold. In the reduction direction, all isoforms inactivated 5α-dihydrotestosterone (17β-hydroxy-5α-androstan-3-one; 5α-DHT) to yield 5α-androstane-3α,17β-diol (3α-androstanediol). However, only AKR1C3 reduced ∆4-androstene-3,17-dione to produce significant amounts of testosterone. All isoforms reduced oestrone to 17β-oestradiol, and progesterone to 20α-hydroxy-pregn-4-ene-3,20-dione (20α-hydroxyprogesterone). In the oxidation direction, only AKR1C2 converted 3α-androstanediol to the active hormone 5α-DHT. AKR1C3 and AKR1C4 oxidized testosterone to ∆4-androstene-3,17-dione. All isoforms oxidized 17β-oestradiol to oestrone, and 20α-hydroxyprogesterone to progesterone. Discrete tissue distribution of these AKR1C enzymes was observed using isoform-specific reverse transcriptase-PCR. AKR1C4 was virtually liver-specific and its high kcat/Km allows this enzyme to form 5α/5β-tetrahydrosteroids robustly. AKR1C3 was most prominent in the prostate and mammary glands. The ability of AKR1C3 to interconvert testosterone with ∆4-androstene-3,17-dione, but to inactivate 5α-DHT, is consistent with this enzyme eliminating active androgens from the prostate. In the mammary gland, AKR1C3 will convert ∆4-androstene-3,17-dione to testosterone (a substrate aromatizable to 17β-oestradiol), oestrone to 17β-oestradiol, and progesterone to 20α-hydroxyprogesterone, and this concerted reductive activity may yield a pro-oesterogenic state. AKR1C3 is also the dominant form in the uterus and is responsible for the synthesis of 3α-androstanediol which has been implicated as a parturition hormone. The major isoforms in the brain, capable of synthesizing anxiolytic steroids, are AKR1C1 and AKR1C2. These studies are in stark contrast with those in rat where only a single AKR with positional- and stereo-specificity for 3α-hydroxysteroids exists.

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11?-Hydroxysteroid dehydrogenase Type 1 in obesity and Type 2 diabetes

Diabetologia ◽

10.1007/s00125-003-1284-4 ◽

2004 ◽

Vol 47 (1) ◽

pp. 1-11 ◽

Cited By ~ 78

Author(s):

T. M. Stulnig ◽

W. Waldh�usl

Keyword(s):

Type 2 Diabetes ◽

Hydroxysteroid Dehydrogenase

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Characterization of rat 17β-hydroxysteroid dehydrogenase type 1 gene and mRNA transcripts

Gene ◽

10.1016/s0378-1119(97)00669-0 ◽

1998 ◽

Vol 208 (2) ◽

pp. 229-238 ◽

Cited By ~ 7

Author(s):

Lateef A Akinola ◽

Matti Poutanen ◽

Hellevi Peltoketo ◽

Reijo Vihko ◽

Pirkko Vihko

Keyword(s):

Hydroxysteroid Dehydrogenase ◽

Mrna Transcripts

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Characterization of damage and biotic factors associated with the decline of Eucalyptus wandoo in southwest Western Australia

Canadian Journal of Forest Research ◽

10.1139/x05-162 ◽

2005 ◽

Vol 35 (11) ◽

pp. 2589-2602 ◽

Cited By ~ 16

Author(s):

Ryan J Hooper ◽

K Sivasithamparam

Keyword(s):

Western Australia ◽

Partial Harvest ◽

Foliage Density ◽

Density Ratios ◽

The Relationship ◽

Mixed Age ◽

Eucalyptus Wandoo

Crown decline of wandoo, Eucalyptus wandoo, in southwest Western Australia has escalated over the last 10 years, so very few unaffected stands remain. To assess the canopy-damage characteristics of trees in decline a destructive, partial-harvest method was used to sample branches in natural mixed-age stands. Necrosis of common cankers was closely associated with type-1 borer damage, characterized by "longitudinal" gallery structure on declining trees only. Cankers were found to be consistently more severe on declining trees, with decay regions affecting a greater proportion of sapwood tissue. Several infestations causing type-1 borer damage that varied in age were found on declining branches, providing evidence of cyclical damage events. Type-2 borer damage characterized by "ring-barking" gallery structure caused extensive damage in canopies, but was not always associated with decline. Interactions between foliage density and canker score showed that 17.8% and 63.1% of the variability in foliage-density ratios was accounted for in declining intermediate-health and unhealthy classes, respectively. The relationship was negligible for the healthy class (9.9%), providing strong evidence that cankers are causing foliage loss in declining canopies. Evidence suggests that an interaction between type-1 borer infestations and decay-causing fungi is responsible for the decline in E. wandoo wandoo canopies.

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The Blue Copper-Containing Nitrite Reductase fromAlcaligenes xylosoxidans: Cloning of the nirAGene and Characterization of the Recombinant Enzyme

Journal of Bacteriology ◽

10.1128/jb.181.8.2323-2329.1999 ◽

1999 ◽

Vol 181 (8) ◽

pp. 2323-2329 ◽

Cited By ~ 25

Author(s):

Miguel Prudêncio ◽

Robert R. Eady ◽

Gary Sawers

Keyword(s):

Amino Acid ◽

Nitrite Reductase ◽

Recombinant Enzyme ◽

Leader Peptide ◽

Resonance Spectroscopy ◽

Gene Encoding ◽

Blue Copper

ABSTRACT The nirA gene encoding the blue dissimilatory nitrite reductase from Alcaligenes xylosoxidans has been cloned and sequenced. To our knowledge, this is the first report of the characterization of a gene encoding a blue copper-containing nitrite reductase. The deduced amino acid sequence exhibits a high degree of similarity to other copper-containing nitrite reductases from various bacterial sources. The full-length protein included a 24-amino-acid leader peptide. The nirA gene was overexpressed inEscherichia coli and was shown to be exported to the periplasm. Purification was achieved in a single step, and analysis of the recombinant Nir enzyme revealed that cleavage of the signal peptide occurred at a position identical to that for the native enzyme isolated from A. xylosoxidans. The recombinant Nir isolated directly was blue and trimeric and, on the basis of electron paramagnetic resonance spectroscopy and metal analysis, possessed only type 1 copper centers. This type 2-depleted enzyme preparation also had a low nitrite reductase enzyme activity. Incubation of the periplasmic fraction with copper sulfate prior to purification resulted in the isolation of an enzyme with a full complement of type 1 and type 2 copper centers and a high specific activity. The kinetic properties of the recombinant enzyme were indistinguishable from those of the native nitrite reductase isolated from A. xylosoxidans. This rapid isolation procedure will greatly facilitate genetic and biochemical characterization of both wild-type and mutant derivatives of this protein.

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Genetic Risk Scores for Diabetes Diagnosis and Precision Medicine

Endocrine Reviews ◽

10.1210/er.2019-00088 ◽

2019 ◽

Vol 40 (6) ◽

pp. 1500-1520 ◽

Cited By ~ 34

Author(s):

Miriam S Udler ◽

Mark I McCarthy ◽

Jose C Florez ◽

Anubha Mahajan

Keyword(s):

Risk Scores ◽

Diabetes Diagnosis ◽

Physiological Mechanisms ◽

Risk Variants ◽

Polygenic Scores ◽

Disease Predisposition ◽

Dna Sequence Variants

Abstract During the last decade, there have been substantial advances in the identification and characterization of DNA sequence variants associated with individual predisposition to type 1 and type 2 diabetes. As well as providing insights into the molecular, cellular, and physiological mechanisms involved in disease pathogenesis, these risk variants, when combined into a polygenic score, capture information on individual patterns of disease predisposition that have the potential to influence clinical management. In this review, we describe the various opportunities that polygenic scores provide: to predict diabetes risk, to support differential diagnosis, and to understand phenotypic and clinical heterogeneity. We also describe the challenges that will need to be overcome if this potential is to be fully realized.

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