Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q8NEX9 (reductase)
 26,410 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Parenchymal hepatocytes isolated from adult rats were cultured on three types of collagen-containing substrata: collagen-coated plates, collagen membranes and confluent diploid human fibroblasts. Hepatocytes on the latter two substrata maintained characteristic morphology for at least 10 days in culture, whereas degenerative changes (cell death and formation of multinucleated hepatocytes) and growth of nonparenchymal elements were seen after 5 days in cultures on collagen-coated plates. Parallel findings were seen on basal and induced levels of cytochrome P-450 and NADPH-cytochrome C reductase. The basal levels of cytochrome P-450 were not measurable after day 3 in hepatocytes cultured on collagen-coated plates, whereas measurable levels were maintained in the hepatocytes cultured on the other two substrata. Addition of phenobarbital or methylcholanthrene at day 5 in culture caused an increase in cytochromes P-450 and P-448, respectively, only in hepatocytes cultured on collagen membranes and confluent fibroblasts. Analogous results were seen for the enzyme NADPH-cytochrome C reductase. The similarities in performance between hepatocytes on collagen membranes and on human fibroblasts show that a continuous collagen-containing substratum is important for optimal performance of hepatocytes in primary culture. The possible importance of cultures of hepatocytes on human fibroblasts for carcinogenesis studies is discussed.
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PMID:Primary cultures of hepatocytes on human fibroblasts. 11 6

A fraction greatly enriched in microsomes was prepared from chick embryo limb bone tissue homogenates by differential centrifugation in a high density solution of Metrizamide. This fraction was used to determine the submicrosomal localization of prolyl hydroxylase. At a low concentration (0.05%) of the non-ionic detergents Triton X-100 and Brij-35, 90 to 93% of prolyl hydroxylase activity was released from microsomes. Concentrations of Triton X-100 greater than 0.1% were required to solubilize the intrinsic membrane enzyme NADH-ferricyanide reductase and to release membrane-bound ribosomes, while Brij-35 did not extensively solubilize membrane components even at concentrations up to 0.4%. In addition, prolyl hydroxylase activity which could subsequently be released from microsomes by Brij-35 was relatively resistant to trypsin proteolysis at concentrations which removed more than 50% of the ribosomes and approximately 40% of the protein from microsomes. These results suggest that 90 to 93% of prolyl hydroxylase activity in connective tissue is located within the cisternae of the endoplasmic reticulum. Gel filtration of prolyl hydroxylase released from microsomes or found in the soluble fraction of limb bone homogenates revealed two peaks of activity corresponding to molecular weights of 230,000 and 450,000 to 500,000. The latter is twice the value reported for purified chick embryo prolyl hydroxylase. A fraction of the total prolyl hydroxylase activity (generally 20 to 35%) in microsome preparations could be measured in the absence of detergent, although the microsomal membrane should be impermeable to the large unhydroxylated collagen chains used as substrate. On the basis of experimental data, it was concluded that detergent-independent activity was most likely due to damaged microsomal membranes and that this damage was sufficient to allow substrate and trypsin to enter the cisternae but not to allow prolyl hydroxylase to be released.
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PMID:Submicrosomal localization of prolyl hydroxylase from chick embryo limb bone. 18 83

Homocystinuria with elevated plasma homocysteine and methionine levels is the result of deficient activity of cystathionine synthetase, the enzyme catalyzing conversion of homocysteine to cystathionine. It is inherited as an autosomal recessive trait with a worldwide distribution. The major clinical manifestations result from the elevated plasma homocysteine level. The excitotoxic effect of homocysteic acid accounts for mental retardation and seizures. Interference with collagen cross-linking by sulfhydryl groups of homocysteine causes ectopia lentis and skeletal deformities. Sulfation factor-like effects contribute to disruption of vascular endothelium, which is followed by platelet thrombosis and widespread arterial and venous occlusions. Low methionine homocystinuria, with deficient remethylation of homocysteine, results from deranged vitamin B(12) metabolism and from deficient 5,10-methylene-tetrahydrofolate reductase. Administration of azaribine produces homocystinuria by mechanism not yet elucidated.
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PMID:Homocystinuria: pathogenetic mechanisms. 32 77

The Living Skin Equivalent (LSE) is an organotypic coculture of human dermal fibroblasts in a collagen-containing matrix and a stratified epidermis composed of human epidermal keratinocytes. In order to establish the feasibility of using this in vitro system as a model for cutaneous biotransformation, the metabolic fate of topically applied testosterone (T) was monitored in the LSE. After a 24-hour exposure period (37 degrees C) to radiolabelled T, LSE extracts analyzed by high-performance thin-layer chromatography showed that approximately 50% of the applied T had been metabolized. Identified metabolites included bands which comigrated with polar metabolites and products of T 5 alpha-reductase. The general distribution of the observed metabolites was similar to that obtained using biopsied human skin. The rates of T penetration (32 degrees C) through the LSE were monitored after application of T in two vehicles (water and petrolatum) and yielded permeability constants (Kps) of 29 and 1.6 x 10(-3) cm/h, respectively. These Kp values were 4- to 6-fold higher than those reported for human abdominal skin, and reflect the vehicle-related shift in penetration seen in human skin. The Kp values for two additional steroids, estradiol and hydrocortisone, and for T were also determined at 22 degrees C and compared to published Kp values. These Kp values in the LSE were, respectively, 63-, 187- and 35-fold higher than those reported for human skin. The data suggest that compared to human skin the LSE has only a partial barrier function to the passage of test chemicals.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Absorption and metabolism of topically applied testosterone in an organotypic skin culture. 144 4

Tissues from human benign prostatic hyperplasia [BPH] were collected from twelve patients undergoing routine transurethral resection of the prostate to relieve urine out-flow obstruction. Viable epithelial organoids were obtained after enzymatic digestion of the tissue. Primary cultures of epithelium were successfully maintained on collagen gel for up to 21 days. Immunocytochemical staining revealed that there was no expression of either desmin or vimentin in these cells; however, the anticytokeratin antibodies LP-34 (cytokeratins 4, 5, 6, 10, 13, 16, 17 and 18), LE-61 (cytokeratin 18) and CAM 5.2 (cytokeratins 7 and 8) all showed positive responses, indicating the epithelial nature of the cells. Cell growth was significantly increased in the presence of 3 x 10(-10) M testosterone propionate [TP] in the culture medium. The presence of the non-steroidal anti-androgens, Flutamide and Hydroxy-Flutamide [Flu-OH], in the concentration range 1.0-0.001 micrograms per ml of medium inhibited the growth in the presence of androgens in a dose-dependent manner. The anti-androgens failed to affect cell growth in the absence of TP. In view of these preliminary findings, it is postulated that the antiandrogens might be acting either by displacing the androgen from its receptor or alternately by inhibiting the activity of prostatic 5 alpha-reductase.
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PMID:Effects of flutamide and hydroxy-flutamide on the growth of human benign prostatic hyperplasia cells in primary culture: a preliminary report. 172 58

Interpretation of primary monolayer culture of organs and tissues with different epithelial cell types demands well-defined criteria for distinguishing between such cells. Epithelial components in breast carcinomas comprise, in addition to carcinoma epithelial cells (CEP), at least two epithelial cell types organized in mammary ductules of normal appearance as an inner layer of luminal epithelial cells (LEP) and an outer layer of basal or myoepithelial cells (MEP) resting on a basement membrane. In a previous study (Petersen and van Deurs, Cancer Res., 46: 2013-2020, 1986) we have defined a population of CEP in vivo and in vitro, appearing in about 50% of primary carcinomas, by a cytochemical reaction for reduced nicotinamide adenine dinucleotide phosphate neotetrazolium reductase. Carcinoma derived epithelial cells not showing this cytochemical reaction in culture were believed to originate from either carcinoma cells or from mammary ductules of normal or benign appearance. In the present study we show that carcinoma derived NADPH-NT reductase negative cell islets often exhibit phenotypic traits of apparently normal mammary ductules as defined in vivo. Moreover, it is shown that the reductase positive CEP, apart from the reductase reaction, has preserved several other features in culture distinguishing them from cells of apparently normal origin. Thus, whereas reductase positive CEP often consisted of only one cell type, as revealed by phase contrast microscopy, some reductase negative cell islets showed a distinct two-cell-type composition. One cell type exhibited cobblestone-like appearance and remained in the center of the islets whereas the other was more loosely arranged and rapidly left the central area by migration below the cobblestone-like cells to the periphery of the islets. Cobblestone-like cells and loosely arranged cells were found by immunocytochemistry to express elements of LEP and MEP phenotype, respectively. LEP phenotype was defined in vivo by expression of milk fat globule membrane antigen and cytokeratins, whereas MEP expressed basement membrane-associated type IV collagen. Computerized image analysis revealed mean population doubling times for cells with MEP phenotype of 1 day and for those with LEP phenotype of 2 days. Both cell types showed a diploid DNA pattern as revealed by fluorimetry. Reduced nicotinamide adenine dinucleotide phosphate neotetrazolium reductase positive CEP expressed milk fat globule membrane antigen and cytokeratins, thus resembling the reductase negative LEP.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Preservation of defined phenotypic traits in short-term cultured human breast carcinoma derived epithelial cells. 310 27

6-Methylene progesterone (6MP) is an irreversible in vitro kcat inhibitor of rat prostate 5 alpha-reductase, the enzyme which converts testosterone (T) to dihydrotestosterone (DHT). Treatment of adult rats with 6MP or diethylstilbestrol (DES) decreased the weight of the ventral prostate (VP) by 45%, while castration reduced it by 86%. Histologically, the 6MP-treated VP were indistinguishable from those of controls, while the VP from DES-treated rats showed fibrous stromal hypertrophy as in castrated rats. The prostatic hydroxyproline content, an index of collagen levels, was enhanced by castration or DES, but was not significantly increased by 6MP. Within 2 days of 6MP treatment, the 5 alpha-reductase activity was reduced by 46% and ornithine decarboxylase (ODC) activity was lowered by 27%. During this time the prostatic acid phosphatase activity increased 42% and remained elevated with continued exposure to 6MP up to 13 days. The castration-induced involution of the VP was accompanied by a reduction in serum T and an increase in serum luteinizing hormone (LH). 6MP had no effect on T and LH serum levels but reduced the DHT content within the VP by 64%. Our results indicate that the structure and secretory acid phosphatase activity of the VP are less sensitive to changes in the ratio of T:DHT than is cell proliferation. Thus, the relative amounts of DHT and T within the VP may prove to be more significant than the absolute amount of either androgen in controlling prostate growth or its attendant neoplasms.
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PMID:A comparison of the effects of castration and 6-methylene progesterone, a 5 alpha-reductase inhibitor, on the rat ventral prostate. 343 60

Gossypol acetic acid (GAA) at the dosage of 30 mg/kg daily for 2 weeks could prolong the sleeping time of pentobarbital, increase the SGPT level, decrease the liver concentration of cytochrome P-450 and GSH content, inhibit the activity of cytochrome C reductase and aminopyrine-N-demethylase, but was without effect on cytochrome b5 and aniline hydroxylase. At a smaller daily dosage (15 mg/kg for 4 weeks), GAA could induce the rise of SGPT level and GSH content without affecting the liver metabolizing enzymes. GAA at both dosages could induce marked pathological changes of liver cells in treated rats, such as vacuolation of mitochondria, dilation of endoplasmic reticulum and widening of perinuclear space as well as proliferation of collagen fibers in Disse's spaces. GAA could induce the formation of O2 and H2O2 and could inhibit Ca2+ sequestration in rat liver microsomes in vitro. [C14]-gossypol could bind to microsomal protein irreversibly either in the presence or absence of NADPH. It may be concluded that GAA is capable of causing damage to liver cells.
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PMID:Hepatotoxicity of gossypol in rats. 362 95

Temporal and spatial patterns of lipid deposition, vascularization and collagen deposition were described for subcutaneous adipose tissue in the fetal pig. Enzyme cytochemical changes were reported as they relate to the morphological differentiation of the subcutaneous depot. There are distinct temporal lags between the appearance of specific enzymes in adipocytes. For example, NADH-tetrazolium reductase activity appeared earliest whereas esterase activity appeared before lipoprotein lipase (LPL) activity. Adipose tissue primordia has been localized around specific tissue components in rat and pig tissues. These tissue components include hair follicles, sweat glands, large nerves, large blood vessels and mammary gland ducts. Lipid and enzyme cytochemistry demonstrates physical continuity between primordial cells and differentiated fat cell clusters. Alterations in maternal and/or fetal endocrine or metabolic profiles result in specific changes in fetal subcutaneous adipocytes. For example, maternal diabetes significantly increases cell size whereas genetic obesity has little effect on cell size but increases cellular LPL activity significantly. A comparison of subcutaneous and perirenal depots in the pig fetus indicated several depot specific anatomical and enzyme histochemical traits. Blood vessel architecture and vascular alkaline phosphatase activity clearly demarcated perirenal and subcutaneous depots in the fetus. These data indicate that site to site variations of adipose tissue characteristics may be reflecting intrinsic stromal-vascular aspects of specific locations.
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PMID:Anatomical and enzyme histochemical differentiation of adipose tissue. 393 90

Male pseudohermaphroditism due to partial androgen insensitivity (PAI) may be suspected clinically in case of incomplete masculinization of external genitalia in spite of age related plasma androgen levels. In 25 children or adolescents in whom PAI was suspected, the 5 alpha-reductase activity of external genitalia fibroblasts, the number of androgen receptor sites (Bmax) and the affinity of receptors for dihydrotestosterone (Kd) were studied. Clinical expression of PAI is highly polymorphic (Prader's type I to type IV), when most children (18/25) were considered as males. In a single patient the very low 5 alpha-reductase activity permitted the diagnosis of 5 alpha-reductase deficiency. The number of receptor sites (fmoles/mg DNA) varied from 0 to 730. Mean Bmax of patients (282 +/- 187 fmoles/mg DNA) was statistically lower than that of normal subjects (642 +/- 220 fmoles/mg DNA), p less than 0.05. The 5 cases in whom receptor concentrations were normal may be related to a qualitative abnormality of the androgen receptor or to a "post-receptor" defect. On the contrary no significant differences in Kd values were found. Correlation between sexual ambiguity and the number of measured receptors was not possible. These results emphasize the clinical and biochemical heterogeneity of PAI. Nevertheless, the decrease in number of androgen receptor sites remains the major data for the biochemical diagnosis of PAI. Study of post-receptor "markers" (3 alpha-reductase activity, aromatase, collagen) might allow better analysis of cases with PAI in whom androgen receptor concentrations are normal.
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PMID:[Male pseudohermaphroditism caused by partial insensitivity to androgens. Clinical and biochemical heterogeneity]. 408 89


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