Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 40
Filtrar
1.
Endocrinology ; 106(6): 1880-5, 1980 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-6966217

RESUMEN

The activity and kinetics of delta 5-3 beta-dehydrogenase and 17 alpha-hydroxylase, using labeled pregnenolone as substrate, were measured in gonadal homogenates from rats fed alcohol or isocalorically substituted carbohydrate for 40 days. There was no difference in the rate or reaction kinetics for either enzyme noted between control and alcohol-treated animals when the assays were carried out in the presence of saturating amounts of exogenous pyridine nucleotide cofactors. However, when exogenous cofactors were omitted from the reaction mixture, there was decreased activity of the delta 5-3 beta-dehydrogenase system and increased activity of the 17 alpha-hydroxylase reaction. Furthermore, a cofactor-specific inhibiting effect on delta 5-3 beta-dehydrogenase activity by NADH and NADPH was found. Incubation of gonadal homogenates from the alcohol-treated animals with pyruvate on lactate (in the absence of exogenous cofactors) resulted in an increase and a decrease, respectively, in enzyme activity. These studies indicate that chronic alcohol use decreases gonadal delta 5-3 beta-dehydrogenase activity and that this is most likely due to an effect of the agent on the concentration and/or availability of pyridine nucleotide cofactors rather than to a direct effect on the enzyme. This phenomenon may account for the mechanism by which alcohol decreases testosterone secretion in these animals.


Asunto(s)
Etanol/farmacología , Pregnenolona/metabolismo , Esteroides/biosíntesis , Testículo/metabolismo , Animales , Cinética , Masculino , Progesterona Reductasa/metabolismo , Ratas , Esteroide 17-alfa-Hidroxilasa/metabolismo , Testículo/efectos de los fármacos
2.
J Clin Endocrinol Metab ; 47(6): 1378-82, 1978 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-263357

RESUMEN

The cytoplasm of normal human male and female gingiva contains a receptor capable of specifically binding 5 alpha-dihydrotestosterone (DHT). This binding has a high affinity for DHT (Kd, approximately 2.2 x 10-9 M) and a low capacity (approximately 190 fmol/mg protein). The binding is extremely heat sensitive and exhibits a pattern of competition similar to that obtained with DHT receptors from other target tissues. The demonstration of a specific DHT receptor in human gingiva provides the first direct biochemical evidence that this tissue may function as a target organ for androgens. There was no correlation between the Kd in normal tissue and gingival hyperplasia or between the Kd or number of binding sites and the age or sex of the patient. However, there sites and the age or sex of the patient. However, there was a significant difference (P less than 0.0005) between the amount of DHT-binding sites per mg protein in normal tissue as compared to gingival hyperplasia (drugs or pregnancy).


Asunto(s)
Encía/metabolismo , Receptores Androgénicos/metabolismo , Receptores de Esteroides/metabolismo , Adolescente , Adulto , Unión Competitiva , Niño , Dihidrotestosterona/metabolismo , Estabilidad de Medicamentos , Femenino , Hiperplasia Gingival/metabolismo , Calor , Humanos , Cinética , Masculino , Persona de Mediana Edad
3.
J Clin Endocrinol Metab ; 54(3): 608-12, 1982 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-7035487

RESUMEN

The cytoplasm of normal human male and female gingiva contains a receptor capable of specifically binding 17 beta-estradiol and moxestrol (R-2858) with high affinity (Kd = approximately 3.4 X 10(-10) M) and low capacity (4.5 fmol/mg protein). The binding is sensitive to heat (destroyed by warming to 37 C for 60 min), proteolytic enzymes (pronase, trypsin, and chymotrypsin), and exhibits a pattern of competition similar to that obtained with estrogen receptors from other target tissues. Nuclear uptake of [3H]estradiol was demonstrated by using a dry autoradiographic technique. Specific nuclear localization of [3H]estradiol was found predominantly in basal and spinous layers of gingival epithelium, stromal connective tissue cells (fibroblasts), and endothelial cells and pericytes of small blood vessels in the lamina propria. There was no difference between the Kd values in normal and diseased tissue or between the Kd values or number of binding sites and the age or sex of the patient. However, there was a difference between the amount of estrogen binding sites per mg protein in normal tissue compared to gingiva with dilantin hyperplasia. These results provide the first direct evidence that human gingiva may function as a target organ for estrogens.


Asunto(s)
Encía/metabolismo , Receptores de Estrógenos/metabolismo , Adolescente , Adulto , Anciano , Autorradiografía , Unión Competitiva , Niño , Estabilidad de Medicamentos , Endopeptidasas/farmacología , Estradiol/metabolismo , Etinilestradiol/análogos & derivados , Etinilestradiol/metabolismo , Femenino , Histocitoquímica , Calor , Humanos , Masculino , Persona de Mediana Edad , Receptores de Estrógenos/efectos de los fármacos
4.
Invest Ophthalmol Vis Sci ; 24(10): 1413-7, 1983 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-6618802

RESUMEN

Cells cultured from trabecular meshwork specimens obtained from patients with primary open angle glaucoma (TMPOAG cells) exhibited two major differences in cortisol-metabolizing enzymes when compared with similar cells from nonglaucomatous patients. One is a marked increase (greater than 100-fold) in delta 4-reductase activity and the other is a decrease (4-fold) in 3-oxidoreductase activity. Peripheral lymphocytes from one of these patients as well as from five additional patients with POAG, did not show these abnormalities, indicating that the defects are not found in all cortisol-metabolizing cells. The abnormal metabolism of cortisol by TMPOAG cells may be of significance in the pathogenesis of POAG.


Asunto(s)
Glaucoma de Ángulo Abierto/metabolismo , Hidrocortisona/metabolismo , Malla Trabecular/metabolismo , Adulto , Anciano , Células Cultivadas , Femenino , Humanos , Linfocitos/metabolismo , Masculino , Persona de Mediana Edad , Oxidorreductasas/análisis
5.
Invest Ophthalmol Vis Sci ; 32(7): 2130-5, 1991 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-2055703

RESUMEN

Glucocorticoids have long been implicated in the etiology of primary open-angle glaucoma (POAG) and cataract. Cortisol metabolites have biologic activity and may affect aqueous humor dynamics. This study was done to determine whether these metabolites are found in human aqueous humor and can be produced by ocular tissues. Radioimmunoassays (RIA) were developed for 5 alpha-dihydrocortisol (5 alpha-DHF) and 5 beta-dihydrocortisol (5 beta-DHF). These assays, as well as a cortisol RIA, were used to quantify these three steroids in 20 surgically derived aqueous humor specimens from patients with and without POAG. The mean concentrations of cortisol and 5 alpha-DHF were 2.5 and 1.3 ng/ml, respectively. In the small group studied, there was no statistically significant difference between the aqueous humor steroid levels in patients with and without POAG. The amount of 5 beta-DHF was at the lower limits of detection of the assay system and could not be uniquivocally shown. Human lenses metabolized cortisol in vitro to 5 alpha-DHF and 3 alpha,5 alpha-tetrahydrocortisol (3 alpha,5 alpha-THF). There was no 5 beta-DHF or cortisone formed. The 5 alpha-DHF and 3 alpha,5 alpha-THF were identified by their positions on thin-layer chromatography, their retention times on high-performance liquid chromatography, and recrystallization with authentic standards to constant specific activity. The data suggest that the lens is the source of 5 alpha-DHF in aqueous humor.


Asunto(s)
Humor Acuoso/química , Hidrocortisona/análogos & derivados , Hidrocortisona/metabolismo , Cristalino/metabolismo , Anciano , Cromatografía Líquida de Alta Presión , Cromatografía en Capa Delgada , Femenino , Glaucoma de Ángulo Abierto/metabolismo , Humanos , Hidrocortisona/análisis , Técnicas In Vitro , Masculino , Radioinmunoensayo , Tetrahidrocortisol/análisis
6.
Metabolism ; 28(1): 20-4, 1979 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-759822

RESUMEN

Chronic alcohol ingestion in the rat resulted in increased hepatic aromatase activity, elevation of plasma estradiol, and a decrease in plasma testosterone levels. Testicular incubation studies indicated that the source of the estrogen was not of gonadal origin but was, most likely, due to increased peripheral conversion. The failure of HCG in vitro to restore testicular secretion of testosterone to normal levels suggested a direct action of alcohol, or a metabolic product, on gonadal secretory processes, as distinct from trophic hormone effects. This study demonstrates that many of the hormonal alterations seen in cirrhosis of the liver in man may be produced directly by alcohol feeding without cirrhotic changes in the rat.


Asunto(s)
Consumo de Bebidas Alcohólicas , Androstenodiona/metabolismo , Aromatasa/metabolismo , Estradiol/metabolismo , Estrona/metabolismo , Etanol/farmacología , Hígado/enzimología , Oxidorreductasas/metabolismo , Testosterona/metabolismo , Envejecimiento , Animales , Hígado/efectos de los fármacos , Hígado/crecimiento & desarrollo , Masculino , Ratas , Testículo/efectos de los fármacos , Testículo/crecimiento & desarrollo , Testículo/fisiología
7.
J Dent Res ; 58(2): 638-41, 1979 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-283095

RESUMEN

Product activation of 17beta-hydroxysteroid oxidoreductase for testosterone and androstenedione was established using the enzyme preparation from rat oral mucosa. It is suggested that this activation could be due to the conformational changes of the enzyme.


Asunto(s)
17-Hidroxiesteroide Deshidrogenasas/metabolismo , Androstenodiona/metabolismo , Mucosa Bucal/enzimología , Testosterona/metabolismo , Androstenodiona/farmacología , Animales , Sitios de Unión , Citosol/enzimología , Activación Enzimática/efectos de los fármacos , Masculino , Mucosa Bucal/citología , Ratas , Testosterona/farmacología
8.
J Dent Res ; 58(2): 642-5, 1979 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-283096

RESUMEN

Systemic pretreatment of rats with diphenylhydantoin (DPH) or its addition into an in vitro assay increases 5alpha-reduction of testosterone by the oral mucosa. Enzyme kinetic studies showed that DPH binds to the enzyme and probably activates it by an allosteric mechanism.


Asunto(s)
3-Oxo-5-alfa-Esteroide 4-Deshidrogenasa/metabolismo , Mucosa Bucal/enzimología , Oxidorreductasas/metabolismo , Fenitoína/farmacología , Testosterona/metabolismo , Animales , Citosol/enzimología , Activación Enzimática/efectos de los fármacos , Cinética , Masculino , Mucosa Bucal/citología , Ratas
9.
J Dent Res ; 59(12): 2100-3, 1980 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-6942001

RESUMEN

The localization of 3H-dexamethasone in gingiva and in buccal mucosa was investigated radioautographically after systemic administration of the labeled glucocorticoid to rabbits. Tissue samples were processed for dry radioautography of diffusible substances. This study demonstrates localization of 3H-dexamethasone in the nuclei of target cells in the gingival epithelium, stromata, and the walls of blood vessels, and to a lesser degree in the buccal mucosa cells. The findings support the possibility of a direct effect of glucocorticoids via specific hormone cytosol-nuclear receptors in oral tissues.


Asunto(s)
Dexametasona/metabolismo , Encía/anatomía & histología , Mucosa Bucal/anatomía & histología , Receptores de Glucocorticoides/metabolismo , Receptores de Esteroides/metabolismo , Animales , Autorradiografía , Núcleo Celular/ultraestructura , Epitelio/anatomía & histología , Femenino , Encía/irrigación sanguínea , Conejos
11.
J Dent Res ; 57(3): 511-9, 1978 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28342

RESUMEN

Rat oral mucosa microsomal delta4-3-ketosteroid-5alpha-A-ring reductase enzyme system, reducing testosterone and 4-androstenedione, was found to be inducible by systemic administration of medroxyprogesterone acetate (MPA). MPA, when used in a mixture with testosterone and/or 4-androstenedione in vitro, acted as a competitive inhibitor of the reduction of these substrates.


Asunto(s)
3-Oxo-5-alfa-Esteroide 4-Deshidrogenasa/metabolismo , Androstenodiona/metabolismo , Medroxiprogesterona/farmacología , Mucosa Bucal/enzimología , Oxidorreductasas/metabolismo , Androstenodiona/análogos & derivados , Animales , Cinética , Microsomas/enzimología , Mucosa Bucal/metabolismo , NAD/metabolismo , NADP/metabolismo , Ratas , Testosterona/análogos & derivados
12.
J Dent Res ; 61(8): 1010-3, 1982 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-6955335

RESUMEN

Systemic pretreatment of rats with 5,5'-diphenylhydantoin (DPH) or its addition into an in vitro assay increases microsomal hydroxylation of 17 beta-estradiol. This increase depends on the concentration of DPH in the microsomal cell compartment.


Asunto(s)
Estradiol/metabolismo , Mucosa Bucal/metabolismo , Fenitoína/farmacología , Animales , Encía/efectos de los fármacos , Encía/metabolismo , Masculino , Mucosa Bucal/efectos de los fármacos , Ratas , Ratas Endogámicas , Factores de Tiempo
13.
Life Sci ; 37(8): 711-6, 1985 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-4021735

RESUMEN

Simple and sensitive direct RIA for determination of salivary testosterone was developed by using RSL NOSOLVEX TM (125 1) kit produced by Radioassay System Laboratories (Carson, California). In addition, a relationship between salivary and serum free and total testosterone concentrations was studied in randomly selected 45 healthy subjects, 5 females on oral contraceptive pills and 28 hypertensive patients on various treatment regimens. The lowest weight of testosterone detectable by our modified method was equivalent to 1 pg/ml of saliva, taking into account analytical variability. Intra- and interassay coefficients of variation were 5.09 +/- 2.7% and 8.2 +/- 5.9% respectively. Statistically significant correlations were found between salivary and serum free testosterone (r = 0.97) and salivary and serum total testosterone concentrations (r = 0.70-0.87). The exception to this was a group of hypertensive females in which no correlation (r = 0.14) between salivary and total serum testosterone was found. It is also of interest that, while salivary testosterone was significantly increased in subjects taking oral contraceptives and most of the hypertensive patients the total serum testosterone concentration was in normal range. Our findings suggest that determination of salivary testosterone is a reliable method to detect changes in the concentration of available biologically active hormone in the circulation.


Asunto(s)
Saliva/análisis , Testosterona/análisis , Adulto , Anciano , Anticonceptivos Orales , Femenino , Humanos , Hipertensión/metabolismo , Masculino , Menopausia , Persona de Mediana Edad , Radioinmunoensayo
14.
J Periodontol ; 50(5): 254-64, 1979 May.
Artículo en Inglés | MEDLINE | ID: mdl-287781

RESUMEN

The present study evaluates the relationship between periodontal status, concentration of circulating hormones and metabolism of androgens by human male and female gingiva in vitro. In both male and female patients with healthy gingiva the plasma concentration of gonadotropins (LH and FSH) and steroid hormones (testosterone, androstenedione, estradiol-17 beta, progesterone and cortisol) were in a normal range. However, an alteration in the plasma concentration of progesterone was found in both male and female patients with periodontal pathosis. Both androgens (testosterone and androstenedione) were readily metabolized by human gingiva tissue in vitro. The major pathway of the metabolism of testosterone was via the formation of 17 beta-hydroxy-5 alpha-A-ring reduced androgens (5 alpha-dihydrotestosterone and 3 alpha-, 3 beta-androstanediol). In contrast, androstenedione was metabolized mainly to 17-keto-5 alpha-A-ring reduced (5 alpha-androstanedione, androsterone and epiandrosterone) and 17 beta-oxidoreduced (testosterone) compounds. In addition both substrates were metabolized to 5 beta-A-ring reduced androgens (5 beta-dihydrotestosterone, 5 beta-androstanediol and 5 beta-androstanedione). A significant feature of the metabolism of testosterone and androstenedione by inflamed gingiva was an increase of 5 alpha-A-ring reductase activity (mainly the formation of 5 alpha-dihydrotestosterone and 5 alpha-androstanedione) and 17 beta-oxidoreductase activity (mainly the formation of testosterone from androstenedione). The increase in 5 alpha-reductase activity also showed a significant correlation with the plasma progesterone concentration.


Asunto(s)
Androstenodiona/metabolismo , Encía/metabolismo , Testosterona/metabolismo , Adolescente , Adulto , Androstenodiona/análisis , Androstenodiona/sangre , Femenino , Hormona Folículo Estimulante/metabolismo , Encía/análisis , Encía/anatomía & histología , Encía/enzimología , Gingivitis/metabolismo , Humanos , Hormona Luteinizante/metabolismo , Masculino , Persona de Mediana Edad , Enfermedades Periodontales/metabolismo , Índice Periodontal , Factores Sexuales , Testosterona/análisis , Testosterona/sangre
15.
Spec Care Dentist ; 14(5): 198-202, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-7754455

RESUMEN

For this epidemiologic study, 458 individuals with mental retardation and developmental disability (MRDD), from 6 to 87 years old, from the Lower Hudson Valley region of New York, were evaluated for the occurrence of orthodontic anomalies. High occurrence of both anomalies of intermaxillary relation, as determined by Angle's classification, and the anomalies of occlusion were found in these individuals when compared with the general population. An increased incidence of both acquired (i.e., open bite) as well as hereditary (i.e., prognathia) orthodontic anomalies correlated with the severity of mental retardation. In addition, an increased incidence of Angle class II malocclusion was found in persons with cerebral palsy and autism, and an increase of Angle class III malocclusion in persons with autism and Down syndrome. Moreover, it was found that 74% of MRDD persons had definitive malocclusion, while only 37% of the US general population of comparable age has definitive malocclusion. High incidence of malocclusion in this population remained present into old age, mainly due to a lack of treatment and the need to employ non-conventional orthodontic treatment in this population.


Asunto(s)
Atención Dental para la Persona con Discapacidad/estadística & datos numéricos , Discapacidad Intelectual/complicaciones , Maloclusión/epidemiología , Adolescente , Adulto , Distribución por Edad , Anciano , Anciano de 80 o más Años , Distribución de Chi-Cuadrado , Niño , Femenino , Humanos , Incidencia , Discapacidad Intelectual/epidemiología , Masculino , Maloclusión/complicaciones , Persona de Mediana Edad , New York/epidemiología , Caracteres Sexuales , Distribución por Sexo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA