Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 80
Filtrar
Más filtros

Intervalo de año de publicación
1.
J Assist Reprod Genet ; 37(7): 1567-1577, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32594284

RESUMEN

PURPOSE: The state of limited resource settings that Coronavirus (COVID-19) pandemic has created globally should be taken seriously into account especially in healthcare sector. In oncofertility, patients should receive their fertility preservation treatments urgently even in limited resource settings before initiation of anticancer therapy. Therefore, it is very crucial to learn more about oncofertility practice in limited resource settings such as in developing countries that suffer often from shortage of healthcare services provided to young patients with cancer. METHODS: As an extrapolation during the global crisis of COVID-19 pandemic, we surveyed oncofertility centers from 14 developing countries (Egypt, Tunisia, Brazil, Peru, Panama, Mexico, Colombia, Guatemala, Argentina, Chile, Nigeria, South Africa, Saudi Arabia, and India). Survey questionnaire included questions on the availability and degree of utilization of fertility preservation options in case of childhood cancer, breast cancer, and blood cancer. RESULTS: All surveyed centers responded to all questions. Responses and their calculated oncofertility scores showed different domestic standards for oncofertility practice in case of childhood cancer, breast cancer, and blood cancer in the developing countries under limited resource settings. CONCLUSIONS: Medical practice in limited resource settings has become a critical topic especially after the global crisis of COVID-19 pandemic. Understanding the resources necessary to provide oncofertility treatments is important until the current COVID-19 pandemic resolves. Lessons learned will be valuable to future potential worldwide disruptions due to infectious diseases or other global crises.


Asunto(s)
Betacoronavirus/patogenicidad , Infecciones por Coronavirus/prevención & control , Atención a la Salud/normas , Preservación de la Fertilidad/métodos , Neoplasias/terapia , Pandemias/prevención & control , Neumonía Viral/prevención & control , Betacoronavirus/aislamiento & purificación , COVID-19 , Infecciones por Coronavirus/transmisión , Infecciones por Coronavirus/virología , Atención a la Salud/economía , Países en Desarrollo , Femenino , Preservación de la Fertilidad/economía , Preservación de la Fertilidad/estadística & datos numéricos , Humanos , Neoplasias/virología , Neumonía Viral/transmisión , Neumonía Viral/virología , SARS-CoV-2 , Encuestas y Cuestionarios
2.
Clin Endocrinol (Oxf) ; 72(5): 654-60, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-19681912

RESUMEN

OBJECTIVE: Active acromegaly is associated with increased mortality from cardiovascular causes. Several studies have shown increased atherogenic risk factors and biomarkers of inflammation and atherosclerosis in association with growth hormone excess. The aim of this study was to evaluate oxidized low density lipoprotein (oxLDL) levels and some modulators of LDL oxidative modification in patients with acromegaly. DESIGN: Open transversal study. PATIENTS: Fifteen patients with active acromegaly and 15 controls were studied. MEASUREMENTS: We evaluated the levels of oxLDL, thiobarbituric acid reactive substances (TBARS), ceruloplasmin, bilirubin, uric acid and total reactive antioxidant potential, and the activities of ceruloplasmin, myeloperoxidase, superoxide distmutase, paraoxonase 1, and platelet activating factor acethylhydrolase. Statistical analysis was performed including body mass index as a covariate or as a fixed variable. RESULTS: Patients with acromegaly showed significantly higher levels of oxLDL (120 +/- 19 vs. 86 +/- 20 U/l, P < 0.001) and endothelin (P < 0.05), increased ceruloplasmin activity (P < 0.01) and a trend towards higher values in TBARS concentration (P = 0.07) in comparison to healthy controls. OxLDL was positively associated with GH, IGF-I and its binding protein 3 (r = 0.63, P < 0.001; r = 0.53, P < 0.01; and r = 0.56, P < 0.01; respectively). OxLDL showed direct associations with endothelin-1 (r = 0.53, P < 0.01) and ceruloplasmin activity (r = 0.43, P < 0.05). The other parameters evaluated were similar in both groups. CONCLUSIONS: The increase in plasma oxLDL levels, a direct marker of the plaque formation, could constitute a link between atherosclerosis and active acromegaly. LDL oxidation would not be the consequence of diminished antioxidant defences, but of an enhancement in prooxidant factors like ceruloplasmin.


Asunto(s)
Acromegalia/sangre , Ceruloplasmina/análisis , Lipoproteínas LDL/sangre , 1-Alquil-2-acetilglicerofosfocolina Esterasa/sangre , Acromegalia/metabolismo , Acromegalia/patología , Adulto , Anciano , Anciano de 80 o más Años , Bilirrubina/sangre , Índice de Masa Corporal , Endotelina-1/sangre , Femenino , Hormona de Crecimiento Humana/sangre , Hormona de Crecimiento Humana/metabolismo , Humanos , Proteína 3 de Unión a Factor de Crecimiento Similar a la Insulina/sangre , Factor I del Crecimiento Similar a la Insulina/análisis , Masculino , Persona de Mediana Edad , Análisis Multivariante , Peroxidasa/sangre , Superóxido Dismutasa/sangre , Sustancias Reactivas al Ácido Tiobarbitúrico/análisis , Ácido Úrico/sangre
3.
J Physiol Biochem ; 65(4): 329-37, 2009 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-20358345

RESUMEN

11 beta-hydroxysteroid dehydrogenase (HSDs) enzymes regulate the activity of glucocorticoids in target organs. HSD1, one of the two existing isoforms, locates mainly in CNS, liver and adipose tissue. HSD1 is involved in the pathogenesis of diseases such as obesity, insulin resistance, arterial hypertension and the Metabolic Syndrome. The stress produced by HCl overload triggers metabolic acidosis and increases liver HSD1 activity associated with increased phosphoenolpyruvate carboxykinase, a regulatory enzyme of gluconeogenesis that is activated by glucocorticoids, with increased glycaemia and glycogen breakdown. The aim of this study was to analyze whether the metabolic modifications triggered by HCl stress are due to increased liver HSD1 activity. Glycyrrhetinic acid, a potent HDS inhibitor, was administered subcutaneously (20 mg/ml) to stressed and unstressed four months old maleSprague Dawley rats to investigate changes in liver HSD1, phosphoenolpyruvate carboxykinase (PECPK) and glycogen phosphorylase activities and plasma glucose levels. It was observed that all these parameters increased in stressed animals, but that treatment with glycyrrhetinic acid significantly reduced their levels. In conclusion, our results demonstrate the involvement of HSD1 in stress induced carbohydrate disturbances and could contribute to the impact of HSD1 inhibitors on carbohydrate metabolism and its relevance in the study of Metabolic Syndrome Disorder and non insulin-dependent diabetes mellitus.


Asunto(s)
11-beta-Hidroxiesteroide Deshidrogenasas/biosíntesis , 11-beta-Hidroxiesteroide Deshidrogenasas/fisiología , Glucosa/metabolismo , Hígado/enzimología , Tejido Adiposo/metabolismo , Animales , Metabolismo de los Hidratos de Carbono , Carbohidratos/química , Sistema Nervioso Central/embriología , Ácido Glicirretínico/metabolismo , Hígado/metabolismo , Masculino , Modelos Biológicos , Fosfoenolpiruvato Carboxiquinasa (ATP)/metabolismo , Isoformas de Proteínas , Ratas , Ratas Sprague-Dawley
4.
Int J Biochem Cell Biol ; 33(6): 621-30, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11378443

RESUMEN

The aims of the present work were: (1) to investigate whether the strong decrease of liver uroporphyrinogen decarboxylase (UroD) activity observed in experimental porphyria cutanea tarda is due to alteration of the enzymatic protein and (2) to improve the knowledge about the normal liver enzyme. With these purposes, several physicochemical studies for enzymatic characterization were carried out comparatively on the 12-fold purified liver enzyme of both normal and hexachlorobenzene porphyric rat. The study shows that the enzyme from porphyric rats has a higher activation energy, lower reactivity index and lower optimum pH than the normal one. In addition, it did not reach the Vmax at any of the substrate concentrations assayed (up to 28 microM uroporphyrinogen III), while the normal enzyme reached the plateau around 14 microM. The porphyric enzyme appears to be more protected than the normal against the inhibitory action of several metals, particularly Cu2+ and Pb2+, and against thermal inactivation. Zn2+ did not affect enzymatic activity, whereas Cu2+, Hg2+, Fe2+, Pb2+, and Cd2+ lowered the activities of both normal and porphyric enzyme in a dose-related way. It was also observed that the larger the atomic radius in its hydrated state, the lower the effect of the metal. Neither glutathione nor dithiothreitol significantly altered enzymatic activity in the range of concentrations assayed. beta-Mercaptoethanol had diverse effects, as regards both the concentration assayed and the enzymatic sample used. Assays with cystine showed a dual behaviour of both normal and porphyric enzymatic activity. Western blots for both preparations revealed a single band (65 kDa) with a similar intensity. This study show that hexachlorobenzene treatment modifies the physicochemical properties of liver UroD leading to a sharp decrease of its activity, without affecting its antigenic reactivity probably as a consequence of changes at the conformational level promoted by the binding of its reported inhibitor.


Asunto(s)
Fungicidas Industriales/metabolismo , Hexaclorobenceno/metabolismo , Hígado/enzimología , Uroporfirinógeno Descarboxilasa/metabolismo , Animales , Antígenos/inmunología , Femenino , Fungicidas Industriales/farmacología , Hexaclorobenceno/farmacología , Concentración de Iones de Hidrógeno , Hígado/efectos de los fármacos , Ratas , Ratas Wistar , Temperatura
5.
Int J Biochem Cell Biol ; 29(2): 335-44, 1997 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9147135

RESUMEN

A great deal of information concerning the effects of hexachlorobenzene on the haem metabolic pathway has been obtained but little is known about the effects of the drug on lipid metabolism. Consequently, the time course of phospholipid metabolism alteration caused by this xenobiotic was evaluated as related to changes in porphyrin metabolism with the aim to understand better the interregulation of both metabolisms. Female Wistar rats were treated with HCB (1 g/kg) over a 1-8 week period. Individual phospholipid content, [32P] incorporation, total lipid content, lipid peroxidation, uroporphyrinogen decarboxylase activity, its inhibitor generation and porphyrin content, were the parameters measured in the liver of treated rats. Phospholipid metabolism-with the exception of sphingomyelin-presents a biphasic behaviour, in both the endogenous contents and de novo synthesis. The turning point between both phases is the time at which levels of porphyrin and conjugated dienes increase, the latter compounds being involved in oxidative processes. On the other hand, sphingomyelin decreases continuously during the 8 weeks of treatment. It was also found that the malondialdehyde content increased during the early stages. The time sequence for haem metabolism parameters showed that the accumulation of porphyrins occurs after the decrease in uroporphyrinogen decarboxylase activity and the enzyme inhibitor formation, which are early events (first and second weeks). Porphyrins could not by themselves exacerbate uroporphyrinogen decarboxylase impairment or inhibitor generation. This study shows that hexachlorobenzene alters simultaneously phospholipid and porphyrin metabolisms from the early stages, and generates an oxidative environment that favours porphyrinogens and lipid oxidation at later stages. So, this oxidative environment links the alterations on both metabolisms.


Asunto(s)
Fungicidas Industriales/toxicidad , Hexaclorobenceno/toxicidad , Metabolismo de los Lípidos , Porfirias/inducido químicamente , Animales , Femenino , Peroxidación de Lípido , Porfirias/metabolismo , Ratas , Ratas Wistar
6.
Cancer Lett ; 58(3): 225-32, 1991 Jul 04.
Artículo en Inglés | MEDLINE | ID: mdl-1649694

RESUMEN

The response of female BDVI rats bearing diethylnitrosamine(DENA)-induced hepatic tumors to the porphyrinogenic action of hexachlorobenzene (HCB) was studied. (1) The heme pathway operates in these tumors but they were less affected by HCB than the liver. (2) Tumors did not accumulate porphyrins although the surrounding liver accumulated more porphyrins than livers treated with HCB. (3) DENA/HCB livers which developed a well defined tumor showed slightly less porphyrinogen carboxylyase inhibition and delta-aminolaevulinate synthase induction than HCB rats. (4) The results of the present work suggest that endogenously formed porphyrins would be unable to be accumulated by DENA-induced tumors when the tumoral development precedes the onset of the porphyria.


Asunto(s)
Carcinoma Hepatocelular/complicaciones , Dietilnitrosamina/farmacología , Hexaclorobenceno/farmacología , Neoplasias Hepáticas/complicaciones , Porfirias/metabolismo , 5-Aminolevulinato Sintetasa/metabolismo , Ácido Aminolevulínico/orina , Animales , Carcinoma Hepatocelular/inducido químicamente , Carcinoma Hepatocelular/metabolismo , Sistema Enzimático del Citocromo P-450/metabolismo , Femenino , Ferroquelatasa/metabolismo , Hígado/metabolismo , Neoplasias Hepáticas/inducido químicamente , Neoplasias Hepáticas/metabolismo , Porfobilinógeno/orina , Porfirias/etiología , Porfirinas/metabolismo , Ratas
7.
Biochem Pharmacol ; 35(14): 2399-405, 1986 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-3741545

RESUMEN

The present work deals with the effect of desferrioxamine (DF) on hexachlorobenzene (HCB)-induced porphyria in female rats with the purpose of further investigation of the role of iron in the development of this porphyria. The results obtained show that the repeated injection of DF (three times a week: 100 mg/kg each i.m.) delayed and diminished remarkably the urinary excretion of precursors and porphyrins as well as the accumulation of the latter in liver promoted by HCB (1 g/kg daily given by stomach tube). This was probably due to attenuation by DF of the alterations produced by the fungicide in the two key enzymes: porphyrinogen carboxy-lyase (PCL) and delta-aminolaevulinate synthase (ALA-S). In fact, DF by reducing liver iron levels produced a smaller decrease of the target enzyme (PCL) and a concomitant smaller induction of ALA-S. DF alone did not modify any of these variables or the liver to body weight ratio. DF added at 10(-2) and 10(-3) M to the incubation media of ALA-S and PCL did not alter either of the enzymatic activities, whether in normal or HCB-porphyric preparations. The results obtained show that DF improved the biochemical picture during HCB porphyria. They suggest that iron plays an indirect role in the decrease of PCL enzyme, possibly at the HCB metabolization step. A common iron-involving mechanism for the production of porphyria by different chlorinated compounds is suggested.


Asunto(s)
Clorobencenos/toxicidad , Deferoxamina/uso terapéutico , Hexaclorobenceno/toxicidad , Porfirias/inducido químicamente , 5-Aminolevulinato Sintetasa/antagonistas & inhibidores , Animales , Peso Corporal/efectos de los fármacos , Carboxiliasas/antagonistas & inhibidores , Deferoxamina/farmacología , Modelos Animales de Enfermedad/metabolismo , Femenino , Hexaclorobenceno/metabolismo , Hierro/metabolismo , Hígado/metabolismo , Tamaño de los Órganos/efectos de los fármacos , Porfirias/metabolismo , Porfirias/prevención & control , Porfirinas/metabolismo , Ratas , Enfermedades de la Piel/metabolismo
8.
Biochem Pharmacol ; 39(5): 817-25, 1990 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-2310407

RESUMEN

The effects of hexachlorobenzene (HCB) administration on the development of porphyria and on changes in thyroid function and thyroid hormone metabolism were examined. Female Wistar rats were treated with HCB for 1 or 8 weeks. At both treatment times liver weight was notably increased with a slight change in thyroid weight at 8 weeks. Serum thyroxine (T4) levels were depressed, whereas levels of triiodothyronine (T3) were not depressed significantly at both treatment times. One or eight weeks of HCB treatment did not alter the incorporation and distribution of [125I] into intrathyroidal aminoacids. A 50% reduction in protein bound iodine (PB[125I]) was seen in both groups of animals. HCB altered [125I]T4 metabolism in rat liver slices, increasing T4 dehalogenation. HCB administration for 1 week did not affect urinary excretion of porphyrins or their precursors, or hepatic porphyrin content. The activity of aminolaevulinate synthase was not affected, but there was a 25% and 51% inhibition in porphyrinogen carboxy-lyase (PCL) activity for the uroporphyrinogen disappearance or the coproporphyrinogen formation respectively. After 8 weeks of HCB administration the rats showed a characteristic porphyria. Our results show that HCB treatment increased hepatic thyroxine metabolism, without alterations in thyroid hormone synthesis. Serum T4 and PCL activity behaved differently in both time- and dose-dependent studies, with serum T4 being the more sensitive parameter which responded at earlier times and lower doses.


Asunto(s)
Clorobencenos/toxicidad , Hexaclorobenceno/toxicidad , Hígado/efectos de los fármacos , Porfirias/inducido químicamente , Glándula Tiroides/efectos de los fármacos , Tiroxina/metabolismo , Triyodotironina/metabolismo , 5-Aminolevulinato Sintetasa/metabolismo , Animales , Peso Corporal/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Femenino , Hexaclorobenceno/administración & dosificación , Radioisótopos de Yodo , Hígado/enzimología , Hígado/metabolismo , Tamaño de los Órganos/efectos de los fármacos , Porfirinas/metabolismo , Ratas , Ratas Endogámicas , Tiroxina/sangre , Triyodotironina/sangre
9.
Clin Chim Acta ; 108(3): 447-56, 1980 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-7471475

RESUMEN

Red cell porphyrinogen carboxy-lyase activity was measured using uroporphyrinogen III as substrate in 18 normal persons, 7 male patients with porphyria cutanea tarda, 3 female patients with erythropoietic protoporphyria and 2 female patients with variegate porphyria. The mean values obtained in normal subjects were 0.151 nmol of uroporphyrinogen disappeared in 30 min per mg of protein, and 0.038 nmol of coproporphyrinogen formed in 30 min per mg of protein. We have not been able to detect significant differences between males and females. In porphyria cutanea tarda the enzyme activity was the same as in normal subjects considering either substrate disappearance or end product formation. The differences were not significant at the p less than 0.05 level. Patients with variegata porphyria also exhibited normal erythrocyte porphyrinogen carboxy-lyase activity. The enzyme activity of erythrocytes from patients with erythropoietic protoporphyria was higher than in normals; mean values for specific activities being 0.204 nmol of uroporphyrinogen disappeared, and 0.071 nmol of coproporphyrinogen formed. The significance of the results with respect to the chemical picture of different porphyrias is discussed.


Asunto(s)
Carboxiliasas/sangre , Eritrocitos/enzimología , Porfirias/enzimología , Uroporfirinógeno Descarboxilasa/sangre , Femenino , Humanos , Masculino , Porfirinógenos/metabolismo
10.
Clin Chim Acta ; 69(3): 375-82, 1976 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-947589

RESUMEN

The present report deals with studies on porphyrins and porphyrinogen carboxy-lyase of red cells and urinary porphyrins from lead-intoxicated rabbits. It was shown that the free erythrocyte porphyrins are mixture of protoporphyrin 9, the main component, and minor proportions of Coproporphyrin, Uroporphyrin III and Phyriaporphyrin. Analysis of the urinary porphyrins deomonstrates the presence of Coproporphyrins III as the major component, together with 15-20% of other porphyrins: 10-14% 5-COOH, 1-2% 6-COOH, 2-3% 7-COOH porphyrin and 1-2% Uroporphyrin III. We have not been able to detect an increase of Uroporphyrin I. Assays of porphyrinogen carboxy-lyase activity in hemolysate supernatant using Uroporphyrinogen III and Phyriaporphyrinogen (Phyria'gen) III as substrates, showed the existence of a slight decrease of both decarboxylase activities, being more affected during the second stage, the Phyria'gen decarboxylation. A possible regulation mechanism responsible for the porphyrin picture is discussed.


Asunto(s)
Intoxicación por Plomo/metabolismo , Porfirinógenos/biosíntesis , Porfirinas/biosíntesis , Animales , Eritrocitos/metabolismo , Femenino , Masculino , Porfirinas/sangre , Porfirinas/orina , Conejos , Uroporfirinógeno Descarboxilasa/sangre
11.
Toxicology ; 149(2-3): 89-100, 2000 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-10967406

RESUMEN

Hexachlorobenzene (HCB) induces porphyria both in humans and rodents, and hepatocarcinoma in rodents. In a previous work we observed that HCB produces a continuous decrease in hepatic sphingomyelin (SM) content in Wistar rats. A distinguishing characteristic of sphingolipids breakdown products is their participation in anti-proliferative and apoptotic processes and in the suppression of oncogenesis. As a first step to elucidate the role of SM decrease in the hepatotoxicity induced by HCB, the present study evaluates the metabolic causes of the continuous decrease in hepatic SM content observed in Wistar rats with HCB intoxication, and its relation with porphyria development. For this purpose, the time-course (3, 7, 15, 21 and 28 days) of the effects of HCB on hepatic SM levels and on some of the enzymes of SM synthesis (serine palmitoyltransferase, SPT) and catabolism (sphingomyelinases, SMases) was followed, using two strains of rats differing in their susceptibility to acquire porphyria: Chbb THOM (low) and Wistar (high). HCB (1 g kg(-1) b.w. per day) was administered by gastric intubation as an aqueous suspension. After 5 days of HCB treatment, animals were allowed a 2-day recovery period without HCB administration. Two phases in the HCB-induced damages to sphingolipid metabolism were observed. The first stage (7 days of treatment), common to both strains of rats, was characterized by a decrease in hepatic SM levels (17-25%) and in SPT activity (50-43%), while strain differences were found for the later stage. In Chbb THOM rats, hepatic SM content was restored to normal values concomitantly with an increase in SPT activity (44%, at day 28), and without any increase in SM catabolism. In addition, the level of the other phospholipids was not altered. In Wistar rats, hepatic SM levels decreased continuously throughout the experiment, accompanied by increases in SPT, acidic sphingomyelinase (A-SMase) and neutral sphingomyelinase (N-SMase) activities (86, 28.5 and 78% increase, respectively). A role for glutathione (GSH) in the interstrain differences or a direct effect of HCB on SM metabolism was not found. The present study: (a) demonstrates that N-SMase, A-SMase, and SPT are some of the enzymes that play a role in the HCB-induced decrease of hepatic SM content; (b) finds that HCB-induced alterations of SM metabolism do not correlate with HCB-induced accumulation of hepatic porphyrins; and (c) proposes a link between HCB-induced alterations in phospholipid pattern and in SM metabolism. The increased SM hydrolysis produced as a consequence of SMases induction could be regarded as a cellular response to liver injury elicited by HCB, perhaps acting through the activation of SM signal transduction pathway delaying the proliferative processes observed after long-term treatment with HCB in some rodent species. However, such protective mechanism appears to be strain-dependent.


Asunto(s)
Aciltransferasas/efectos de los fármacos , Fungicidas Industriales/toxicidad , Hexaclorobenceno/toxicidad , Esfingomielina Fosfodiesterasa/efectos de los fármacos , Aciltransferasas/metabolismo , Animales , Femenino , Glutatión/efectos de los fármacos , Glutatión/metabolismo , Hígado/efectos de los fármacos , Hígado/enzimología , Hígado/metabolismo , Fosfolípidos/metabolismo , Porfirinas/metabolismo , Ratas , Ratas Wistar , Serina C-Palmitoiltransferasa , Especificidad de la Especie , Esfingomielina Fosfodiesterasa/metabolismo , Esfingomielinas/metabolismo , Factores de Tiempo
12.
Steroids ; 62(12): 767-70, 1997 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9434340

RESUMEN

In this paper, we studied the effect of heme availability on corticosterone and aldosterone synthesis in rat adrenal. We found that hemin stimulated corticosterone and aldosterone production in adrenal homogenates in a dose-dependent fashion. Hemin administration to rats also provoked an increase in both corticosterone and aldosterone content in adrenal. 3,5-Diethoxycarbonyl-1,4-dihydro-2,4,6-trimethylpyridine (DDC), an inhibitor of liver ferrochelatase activity, was able to inhibit this enzyme in rat adrenal. This resulted in an impairment of heme concentration and consequently adrenal ALA-synthase and porphyrin content were increased. Thus, it was proven that DDC inhibits heme biosynthesis in adrenal as it does in liver. In vivo experiments with rats showed that DDC was able to partially blocked ACTH-mediated corticosterone and aldosterone production while hemin administration was able to partially restore it. These data indicate that heme availability affects steroid biosynthesis in rat adrenal.


Asunto(s)
Glándulas Suprarrenales/metabolismo , Aldosterona/biosíntesis , Corticosterona/biosíntesis , Hemo/metabolismo , 5-Aminolevulinato Sintetasa/metabolismo , Glándulas Suprarrenales/efectos de los fármacos , Hormona Adrenocorticotrópica/farmacología , Animales , Desoxicorticosterona/metabolismo , Dicarbetoxidihidrocolidina/farmacología , Ferroquelatasa/efectos de los fármacos , Ferroquelatasa/metabolismo , Hemina/farmacología , Hígado/efectos de los fármacos , Hígado/metabolismo , Masculino , Porfirinas/metabolismo , Ratas , Ratas Sprague-Dawley
13.
Toxicol Lett ; 106(2-3): 129-36, 1999 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-10403656

RESUMEN

Hexachlorobenzene, one of the most persistent environmental pollutants, induces uroporphyria and phospholipid alterations in rat liver. Harderian glands produce a secretion that is rich in lipids and accumulate large amounts of protoporphyrin. The aim of the present study was to determine if hexachlorobenzene administration to rats affects phospholipid and porphyrin metabolisms in Harderian glands and if these effects are strain dependent. For this purpose, a time-course study (2, 3 and 4 weeks of hexachlorobenzene treatment) of phospholipid pattern and porphyrin content was performed comparatively in two strains of rats (Wistar and Chbb THOM) which differ in their susceptibility to develop HCB-induced porphyria. Hexachlorobenzene produced decreases in several phospholipid contents, but no changes in phosphatidylcholine levels. While the sphingomyelin/phosphatidylcholine molar ratio remained essentially constant until the third week in Chbb THOM rats, it showed a constant drop in Wistar rats, suggesting a more pronounced alteration of membrane fluidity in the later strain. In regard to porphyrin metabolism, Wistar rats showed an increase in the porphyrin content of the gland, while Chbb THOM animals showed a decrease. The study revealed that not only are the normal parameters of phospholipid and porphyrin metabolism in rat Harderian glands strain dependent, but the response to hexachlorobenzene is also.


Asunto(s)
Fungicidas Industriales/toxicidad , Glándula de Harder/efectos de los fármacos , Hexaclorobenceno/toxicidad , Fosfolípidos/metabolismo , Porfirinas/metabolismo , Animales , Femenino , Glándula de Harder/metabolismo , Ratas , Ratas Wistar , Especificidad de la Especie , Factores de Tiempo
14.
Artículo en Inglés | MEDLINE | ID: mdl-12381387

RESUMEN

We characterized Uroporphyrinogen decarboxylase (UroD) (E.C. 4.1.1.37) in hepatopancreas of the crab Chasmagnathus granulatus as a first step to establish this enzyme as a possible biomarker for environmental contamination. We performed a comparative study of crab UroD with the enzyme UroD present in Wistar rat liver, which is known as a useful indicator of intoxication by polyhalogenated aromatic hydrocarbons (PAHs). The final products were the same in crab and rat UroD: the remaining substrate (8-carboxyl-porphyrinogen), the final product Coproporphyrinogen (4-COOH) and intermediate compounds with 7-, 6- and 5-COOH. The elimination of the second carboxyl group seems to be the rate-limiting step in this multiple decarboxylation, because large amounts of 7-COOH porphyrinogen are accumulated. The V(max)/K(m) ratio was 100-fold higher for rat liver UroD than for crab hepatopancreas UroD, suggesting a higher efficiency of the rat enzyme. Optimum pH for enzyme activity was 7.2 and 6.8 for crab and rat, respectively. Although both systems showed the same optimum temperature (47 degrees C), the activation energy was clearly different, 51.5 kJ/mol for C. granulatus and 5.4 kJ/mol for Rattus norvegicus (Wistar strain). Superdex 75 gel chromatography yielded a single symmetrical peak with an apparent molecular mass of 48+/-3 kDa for crab hepatopancreas UroD, suggesting the existence of only one enzymatic species in C. granulatus.


Asunto(s)
Decápodos/enzimología , Sistema Digestivo/enzimología , Uroporfirinógeno Descarboxilasa/metabolismo , Animales , Descarboxilación , Contaminantes Ambientales/metabolismo , Hidrocarburos Halogenados/metabolismo , Concentración de Iones de Hidrógeno , Cinética , Hígado/enzimología , Porfirinógenos/metabolismo , Ratas , Ratas Wistar , Temperatura , Uroporfirinógeno Descarboxilasa/química
15.
Braz J Med Biol Res ; 35(11): 1273-83, 2002 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-12426626

RESUMEN

We evaluated the porphyrinogenic ability of ethanol (20% in drinking water) per se, its effect on the development of sporadic porphyria cutanea tarda induced by hexachlorobenzene in female Wistar rats (170-190 g, N = 8/group), and the relationship with hepatic damage. Twenty-five percent of the animals receiving ethanol increased up to 14-, 25-, and 4.5-fold the urinary excretion of delta-aminolevulinate, porphobilinogen, and porphyrins, respectively. Ethanol exacerbated the precursor excretions elicited by hexachlorobenzene. Hepatic porphyrin levels increased by hexachlorobenzene treatment, while this parameter only increased (up to 90-fold) in some of the animals that received ethanol alone. Ethanol reduced the activities of uroporphyrinogen decarboxylase, delta-aminolevulinate dehydrase and ferrochelatase. In the ethanol group, many of the animals showed a 30% decrease in uroporphyrinogen activity; in the ethanol + hexachlorobenzene group, this decrease occurred before the one caused by hexachlorobenzene alone. Ethanol exacerbated the effects of hexachlorobenzene, among others, on the rate-limiting enzyme delta-aminolevulinate synthetase. The plasma activities of enzymes that are markers of hepatic damage were similar in all drug-treated groups. These results indicate that 1) ethanol exacerbates the biochemical manifestation of sporadic hexachlorobenzene-induced porphyria cutanea tarda; 2) ethanol per se affects several enzymatic and excretion parameters of the heme metabolic pathway; 3) since not all the animals were affected to the same extent, ethanol seems to be a porphyrinogenic agent only when there is a predisposition, and 4) hepatic damage showed no correlation with the development of porphyria cutanea tarda.


Asunto(s)
Etanol/farmacología , Ferroquelatasa/efectos de los fármacos , Hígado/efectos de los fármacos , Porfiria Cutánea Tardía/inducido químicamente , Solventes/farmacología , Uroporfirinógeno Descarboxilasa/efectos de los fármacos , Animales , Sistema Enzimático del Citocromo P-450/análisis , Modelos Animales de Enfermedad , Femenino , Ferroquelatasa/metabolismo , Hexaclorobenceno , Hígado/enzimología , Hígado/patología , Porfobilinógeno/orina , Porfobilinógeno Sintasa/orina , Porfiria Cutánea Tardía/enzimología , Porfiria Cutánea Tardía/orina , Porfirinas/orina , Ratas , Ratas Wistar , Uroporfirinógeno Descarboxilasa/metabolismo
16.
Tumori ; 77(5): 379-84, 1991 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-1781034

RESUMEN

The present study was undertaken to explore the effect of the presence of hepatic tumors induced by diethylinitrosamine (DENA) on the metabolic heme pathway, and to assess whether these tumors can modify the response of rats to the porphyrinogenic drug hexachlorobenzene (HCB) and whether the above mentioned effects occur to a greater extent in females than males. The results obtained showed that: a) Females were more susceptible to the hepatocarcinogenicity of DENA than males. b) Female normal and DENA treated rats were more susceptible than male rats to the porphyrinogenicity of HCB. c) The presence of hepatic DENA induced tumors could diminish basal hepatic ferrochelatase activity. d) Hepatic tumors could modify the response of animals to a porphyrinogenic drug such as HCB. Thus, both female and male DENA/HBC rats accumulated more porphyrins and showed a lower delta-aminolevulinate synthase and uroporphyrinogen I synthase induction than HCB rats. e) The heme pathway was functional in DENA induced tumors in both male and female rats but they were little affected by HCB.


Asunto(s)
Hemo/metabolismo , Neoplasias Hepáticas Experimentales/enzimología , Porfirias/enzimología , Porfirinas/metabolismo , Caracteres Sexuales , 5-Aminolevulinato Sintetasa/metabolismo , Animales , Carboxiliasas , Sistema Enzimático del Citocromo P-450/metabolismo , Dietilnitrosamina , Femenino , Ferroquelatasa/metabolismo , Hexaclorobenceno , Hidroximetilbilano Sintasa/metabolismo , Neoplasias Hepáticas Experimentales/inducido químicamente , Neoplasias Hepáticas Experimentales/patología , Masculino , Porfirias/inducido químicamente , Ratas
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA