scholarly journals Luteal 20α-hydroxy steroid dehydrogenase and the formation of Δ4-3-oxo steroids in the rat after weaning or treatment with 2-bromo-α-ergocryptine during lactation

1975 ◽  
Vol 152 (3) ◽  
pp. 445-448 ◽  
Author(s):  
R G Rodway ◽  
N J Kuhn
Keyword(s):  
Enzyme Activity ◽  
Dehydrogenase Activity ◽  
Early Lactation ◽  
Early Weaning ◽  
Increased Activity ◽  
Hydroxy Steroid ◽  
Steroid Dehydrogenase

Natural or early weaning of rat litters caused an increased activity of maternal luteal 20α-hydroxy steroid dehydrogenase and a decreased release of delta4-3-oxo steroids in vitro. 2. Compound CB-154 (2-bromo-α-ergocryptine) caused an increase of 20α-hydroxy steroid dehydrogenase activity in mid-lactation but not in early lactation. 3. Prolaction did not prevent these increases in enzyme activity.

scholarly journals Metabolism of 11-oxygenated steroids. Metabolism in vitro by preparations of liver

1968 ◽  
Vol 107 (2) ◽  
pp. 239-258 ◽  
Author(s):  
I. E. Bush ◽  
Sheila A. Hunter ◽  
R. A. Meigs
Keyword(s):  
Guinea Pig ◽  
Dehydrogenase Activity ◽  
Liver Microsomes ◽  
Competitive Inhibitor ◽  
Partial Purification ◽  
Substrate Complex ◽  
Hydroxy Steroid ◽  
Steroid Dehydrogenase

1. The isolation and partial purification of 11β-hydroxy steroid dehydrogenase from rat and guinea-pig liver microsomes has been achieved by conventional methods. 2. The efficiency of different 11-oxygenated steroids as substrates has been examined. The relative efficiencies confirm in the main the stereochemical theory of the enzyme–coenzyme–substrate complex that was proposed earlier on the basis of studies in vivo. Δ4-3-Ketones and 5α-hydrogen steroids are readily metabolized by the enzyme. 5β-Hydrogen steroids and Δ4-3-ketones with certain large α-substituents are metabolized to a limited extent or not at all. Halogen substitution in the 9α-position enhances the rate of reduction of 11-ketones but blocks the oxidation of the related 11β-ols. 3. 9α-Fluorocortisol is a competitive inhibitor of the oxidation of cortisol, but 9α-fluorocortisone is reduced at five to ten times the initial velocity of cortisone. 4. 11β-Hydroxy steroid dehydrogenase activity has been found in liver microsomes of rat, guinea pig, rabbit and calf. 5. Relative substrate efficiencies and Km values are similar in whole (debris-free) homogenates, washed microsomes and acetone-dried powders of washed microsomes. 6. A variety of conditions have been examined for the observation of 11β-hydroxy steroid dehydrogenase activity. NADP(H) is an efficient and NAD(H) a very poor coenzyme for the reaction.

Changes in 3β-hydroxy-Δ5-steroid dehydrogenase activity in granulosa tissue during the ovulatory cycle of the laying hen (Gallus domesticus)

1985 ◽  
Vol 106 (3) ◽  
pp. 269-273 ◽  
Author(s):  
D. G. Armstrong
Keyword(s):  
Enzyme Activity ◽  
Dehydrogenase Activity ◽  
Domestic Fowl ◽  
Ovarian Follicle ◽  
Laying Hen ◽  
Gallus Domesticus ◽  
Ovulatory Cycle ◽  
Lh Surge ◽  
Maximal Plasma ◽  
Steroid Dehydrogenase

ABSTRACT The object of this study was to examine changes in the activity of granulosa 3β-hydroxy-Δ5-steroid dehydrogenase during the ovulatory cycle of the domestic fowl. The enzyme activity in granulosa tissue from the largest follicle increased significantly during the period 8–14 h before an expected ovulation. The increase in activity occurs before the preovulatory surge of LH and near the time of lights off. During the 4–8 h period before an ovulation, i.e. the time of maximal plasma LH concentrations, 3β-hydroxy-Δ5-steroid dehydrogenase activity decreased in granulosa tissue from the largest follicle. This observation is explained by proposing that the enzyme is inhibited by the large amounts of progesterone found in the tissue at this time. The results indicate that important biochemical changes are taking place within granulosa tissue of the largest ovarian follicle before the preovulatory LH surge. J. Endocr. (1985) 106, 269–273

scholarly journals Hormonal control of Luteal 20α-Hydroxy steroid dehydrogenase and Δ5-3β-hydroxy steroid dehydrogenase during luteolysis in the pregnant rat

1975 ◽  
Vol 152 (3) ◽  
pp. 433-443 ◽  
Author(s):  
R G Rodway ◽  
N J Kuhn
Keyword(s):  
Prostaglandin F2α ◽  
Late Pregnancy ◽  
Normal Pregnancy ◽  
Hormonal Control ◽  
Placental Lactogen ◽  
Pregnant Rats ◽  
Pregnant Rat ◽  
Hydroxy Steroid ◽  
Steroid Dehydrogenase

Treatment of pregnant rats with human chorionic gonadotrophin, luteotrophin (luteinizing hormone), luteotrophin-releasing hormone, prostaglandin F2α, aminoglutethimide, or by foetoplacental removal or hysterectomy achieved a common multiple-response pattern, namely increased activity of luteal 20α-hydroxy steroid dehydrogenase with decreased activity of delta5-3β-hydroxy steriod dehydrogenase and release of delta4-3-oxo steroids in vitro. 2. Similar effects of foetoplacental removal are noted in pregnant mice. 3. Gonadotrophin induced lower activities of 20α-hydroxy steroid dehydrogenase, except at the very end of pregnancy, and partly inhibited the induction caused by foetoplacental removal. 4. The results suggest that existence of a placental factor that restrains these changes until the end of normal pregnancy, which is produced in amounts proportional to the number of placentae and is conveyed to the ovary via the blood. 5. This factor was not replaced by prolactin. 6. It is argued that neither placental lactogen nor pituitary luteotrophin participate in the induction of 20α-hydroxy steroid dehydrogenase at late pregnancy in the rat. 7. Aminoglutethimide induced 20α-hydroxy steroid dehydrogenase only in late pregnancy. This was partly reversed by progesterone, wholly reversed by progesterone plus oestrogen, and did not involve the pituitary.

scholarly journals Subcellular distribution of Δ5-3 β-hydroxy steroid dehydrogenase in the granulosa cells of the domestic fowl (Gallus domesticus)

1979 ◽  
Vol 181 (3) ◽  
pp. 685-689 ◽  
Author(s):  
D G Armstrong
Keyword(s):  
Cytochrome Oxidase ◽  
Dehydrogenase Activity ◽  
Granulosa Cells ◽  
Domestic Fowl ◽  
Subcellular Location ◽  
Mitochondrial Activity ◽  
Marker Enzyme ◽  
Postovulatory Follicle ◽  
Hydroxy Steroid ◽  
Steroid Dehydrogenase

1. The distribution of 3 beta-hydroxy steroid dehydrogenase was examined in the subcellular fractions of granulosa cells collected from the ovary of the domestic fowl. 2. 3 beta-hydroxy steroid dehydrogenase activity was observed in the mitochondrial (4000g for 20min) and microsomal (105 000g for 120min) fractions. 3. Approximately three times more 3 beta-hydroxy steroid dehydrogenase activity was associated with the cytochrome oxidase activity (a mitochondrial marker enzyme) in anteovulatory-follicle granulosa cells than with that of the postovulatory follicle. 4. Comparison of the latent properties of mitochondrial 3 beta-hydroxy steroid dehydrogenase with those of cytochrome oxidase and isocitrate dehydrogenase indicated that 3 beta-hydroxy steroid dehydrogenase is located extramitochondrially. 5. This apparent distribution of 3 beta-hydroxy steroid dehydrogenase is explained on the basis that the mitochondrial activity is either an artefact caused by a redistribution in the subcellular location of the enzyme, occurring during homogenization, or by the existence of a functionally heterogeneous endoplasmic reticulum that yields particles of widely differing sedimentation properties.

The effect of prenatal treatment with busulfan on in vitro androgen production by testes from rats of various ages

1985 ◽  
Vol 63 (9) ◽  
pp. 1155-1158 ◽  
Author(s):  
Gwenderlyn F. Jansz ◽  
David K. Pomerantz
Keyword(s):  
Leydig Cells ◽  
Testicular Tissue ◽  
Developmental Changes ◽  
Seminiferous Tubules ◽  
Apparent Paradox ◽  
Old Rats ◽  
Effect Of Treatment ◽  
Hydroxy Steroid ◽  
Steroid Dehydrogenase

Treatment of rats with busulfan in utero severely depletes the germ cell population of the seminiferous tubules. These studies have examined the in vitro capacity of testicular tissue and Leydig cells from such testes to secrete androgens. Leydig cells were identified by staining for 3β-hydroxy steroid dehydrogenase. Rats were studied at several ages to identify any developmental changes in the androgen-secreting capacity of control and treated gonads. At 30 days of age, no effect of treatment on serum androgen was found. At 60 and 90 days of age, treatment caused decreased androgen and increased LH content of the serum. At 12, 30, 60, and 90 days of age, the amount of androgen secreted per milligram of testicular tissue in response to LH was higher in busulfan-treated rats. Leydig cells from 60- and 90-day-old rats which had received busulfan were also hyperresponsive to LH. It was concluded that Leydig cells from testes essentially devoid of germ cells were hyperresponsive to LH. Serum androgen levels were decreased yet androgen production per Leydig cell was increased. A possible explanation of this apparent paradox is that busulfan treatment resulted in decreased numbers of Leydig cells in the gonads.

The effect of five fasciolicides on malate dehydrogenase activity and mortality of Fasciola gigantica, Fasciolopsis buski and Paramphistomum explanatum

1981 ◽  
Vol 55 (2) ◽  
pp. 115-122 ◽  
Author(s):  
A. J. Probert ◽  
R. K. Sharma ◽  
K. Singh ◽  
R. Saxena
Keyword(s):  
Enzyme Activity ◽  
Dehydrogenase Activity ◽  
Malate Dehydrogenase ◽  
Fasciola Gigantica ◽  
High Concentrations ◽  
Fasciolopsis Buski ◽  
Reduced Activity ◽  
Inhibited Enzyme ◽  
Malate Oxidation

ABSTRACTThe effect of oxyclozanide, hexachlorophene, nitroxynil, rafoxanide and diamphenethide on malate dehydrogenase activity of homogenates of Fasciola gigantica, Fasciolopsis buski and Paramphistomum explanatum was investigated. The ratio of oxaloacetate reduction to malate oxidation in homogenates of Fasciola gigantica, Fasciolopsis buski and P. explanatum was 4·5:1, 3·6:1 and 5·2:1 respectively. Oxyclozanide and rafoxanide at 10−3 M inhibited enzyme activity by 100% in homogenates from all three species while hexachlorophene at 10−3M also caused 100% inhibition in homogenates from Fasciola gigantica and P. explanatum but only 65% of malate oxidation in Fasciolopsis buski homogenates. Nitroxynil at 10−3M produced 60% inhibition in F. buski homogenates yet had little effect at this concentration on preparations from the other species. Little inhibition was seen with diamphenethide, even at high concentrations. Rapid death of Fasicola gigantica and P. explanatum resulted in vitro when 10−3M oxyclozanide, hexachlorophene, nitroxynil or rafoxanide, were added to the incubation medium. Fasciolopsis buski was killed by 10−3M oxyclozanide but at this concentration the remaining compounds only caused reduced activity. Assay of malate dehydrogenase following drug treatment in vitro failed to show any appreciable reduction in enzyme activity in Fasciola gigantica and P. explanatum but oxyclozanide and hexachlorophene produced inhibition in Fasciolopsis buski. The mode of action of these compounds is discussed.

3β-HYDROXYSTEROID DEHYDROGENASE ACTIVITY IN THE HUMAN FOETAL TESTIS

1965 ◽  
Vol 48 (3) ◽  
pp. 429-438 ◽  
Author(s):  
A. H. Baillie ◽  
M. Niemi ◽  
M. Ikonen
Keyword(s):  
Dehydrogenase Activity ◽  
Substrate Binding ◽  
Interstitial Cells ◽  
List Type ◽  
Colour Reaction ◽  
Crown Rump Length ◽  
Enzyme Substrate ◽  
Free Steroid ◽  
Hydroxy Steroid ◽  
Steroid Dehydrogenase

ABSTRACT Sections of testes from nine human foetuses ranging in crown-rump length from 3.0 to 18.3 cm were incubated to determine 3β-hydroxy-steroid dehydrogenase activity histochemically with the following steroids: 3β-hydroxy-pregn-5-en-20-one (pregnenolong). 3β,17α-dihydroxy-pregn-5-en-20-one (17α-hydroxypregnenolone). 3β-hydroxy-androst-5-en-17-one (DHA). 3β,17β-dihydroxy-androst-5-ene (androstenediol). 3β-sulphoxy-pregn-5-en-20-one (pregnenolone sulphate). 3β-sulphoxy-1 7α-hydroxy-pregn-5-en-20-one (17α-hydroxy-pregnenolone sulphate) 3β-sulphoxy-androst-5-en-17-one (DHAsulphate). 3β-hydroxy-5α-androstan-17-one (epiandrosterone). Pregnenolone and DHA gave a colour reaction in the interstitium of all testes studied. 17α-hydroxypregnenolone was utilised by testes from foetuses of C-R length 8.8 cm and over, androstenediol by testes from foetuses of C-R length 6.1 cm and over. These facts are thought to support the concept of separate substrate-specific 3β-hydroxysteroid dehydrogenases in the testis. Pregnenolone sulphate was used by the interstitial cells of all testes studied but gave a stronger reaction than the free steroid. 17α-hydroxy-pregnenolone sulphate was used by all foetal testes surveyed. DHA sulphate was not well used by the interstitial cells. The utilisation of steroid sulphates in a different manner from the free steroids in this histochemical system may mean that the presence of a sulphate group affects enzyme-substrate binding or that a steroid sulphatase is involved. Intense formazan deposition followed incubation with epiandrosterone in all testes studied. This seems to imply that a δ5 configuration is not necessary for enzyme-substrate binding.

scholarly journals Metabolism of hydroanthracenones in rabbits

1972 ◽  
Vol 127 (1) ◽  
pp. 119-123 ◽  
Author(s):  
J. S. Robertson ◽  
P. J. Dunstan
Keyword(s):  
Aromatic Aldehyde ◽  
Carbonyl Compounds ◽  
Liver Alcohol Dehydrogenase ◽  
Enzyme Systems ◽  
Oxo Compounds ◽  
Successful Reduction ◽  
Hydroxy Steroid ◽  
Steroid Dehydrogenase

1. The metabolism of 1-oxo-octahydro- and 2- and 9-oxoperhydro-anthracenes was investigated in rabbits. All compounds increased the urinary glucuronide content. 2. The 1-oxo and 2-oxo compounds were reduced to the corresponding alcohols whereas the 9-oxo compound was hydroxylated. 3. The reduction in vitro of these compounds and related ketones was investigated with three different enzyme systems (liver alcohol dehydrogenase, hydroxy steroid dehydrogenase, aromatic aldehyde–ketone reductase) in an attempt to explain the results in vivo. 4. Successful reduction of many ketones with aromatic aldehyde–ketone reductase suggests that the kidney may be of importance in the reduction in vivo of certain cyclic carbonyl compounds.

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