RESUMO
Male meiosis is a complex process whereby spermatocytes undergo cell division to form haploid cells. This review focuses on the role of retinoic acid (RA) in meiosis, as well as several processes regulated by RA before cell entry into meiosis that are critical for proper meiotic entry and completion. Here, we discuss RA metabolism in the testis as well as the roles of stimulated by retinoic acid gene 8 (STRA8) and MEIOSIN, which are responsive to RA and are critical for meiosis. We assert that transcriptional regulation in the spermatogonia is critical for successful meiosis.
Assuntos
Animais , Humanos , Diferenciação Celular/genética , Meiose/efeitos dos fármacos , Espermatogênese/fisiologia , Tretinoína/metabolismoRESUMO
There are a number of sites that are required for the production and/or action of all-trans retinoic acid (ATRA). In particular, interruption of different components of the chain of trafficking and metabolism has been associated with cancers arising in numerous organs of the body. Preliminary work suggests that such interruptions may be a factor in lung disorders induced by the smoke exposure. The active metabolite of retinoid, ATRA offers a therapeutic strategy to protect against functional abnormality in the lung, including chronic obstructive pulmonary disease (COPD). This review deals with the lung retinoid metabolism and mediators of retinoid trafficking and signaling with special emphasis on their roles in health and disease.
Assuntos
Animais , Humanos , Pulmão/metabolismo , Modelos Biológicos , Fosfotransferases/metabolismo , Doença Pulmonar Obstrutiva Crônica/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Retinoides/metabolismo , Transdução de Sinais , Tretinoína/metabolismoRESUMO
The present study was designed to investigate the embryofetotoxicity of vitamin A in protein-energy malnourished animals. Retinyl palmitate (66, 99 and 132 mg/kg) suspendend in corn oil was given by gavage to well-nourished and malnourished rats from gestational days 8 to 10 and cesarean sections were performed on day 20. All fetuses were weighed and examined for malformations before being prepared for skeletal evaluation. The proportion of malformed fetuses was higher in the malnourished group at each one of the three dose levels. The data indicate that malnourished animals are more susceptible to the toxic effects of retinyl esters
Assuntos
Gravidez , Ratos , Animais , Feminino , Anormalidades Congênitas/etiologia , Hipervitaminose A/complicações , Desnutrição Proteico-Calórica/fisiopatologia , Tretinoína/metabolismo , Vitamina A/metabolismo , Peso Corporal , Ratos Endogâmicos , Vitamina AAssuntos
Álcool Desidrogenase/metabolismo , Animais , Hipertireoidismo/induzido quimicamente , Hipotireoidismo/enzimologia , Fígado/enzimologia , Masculino , Oxirredução , Ratos , Retinaldeído/metabolismo , Retinoides/metabolismo , Doenças da Glândula Tireoide/enzimologia , Tiroxina , Tretinoína/metabolismoRESUMO
Desde hace años se conoce que la vitamina A juega un total esencial en varios procesos bioquimicos y fisiológicos como la reproducción, el crecimiento, el desarrollo embrionario y la diferenciación de los tejidos epiteliales. El nuevo interés hacia esta vitamina y hacia los retinoides en general se basa en el hecho de que estas sustancias pueden inhibir el desarrollo de tumores en muchos sistemas experimentales. En efecto se ha demostrado que los retinoides bloquean in vitro la transformación neoplásica producida por cancerigenos químicos, y que, in vivo, pueden prevenir la inducción de tumores por parte de dichos compuestos. Por tanto, los retinoides pueden considerarse potenciales agentes de prevención. El tratamiento con retinoides, sin embargo, se ve dificultado por su toxicidad, especialmente a nivel hepático. La única excepción está representada actualmente por la N-(4-Hydroxy Phenil) Retinamida (HPR), un análogo sintético de la Vitamina A que, a diferencia de muchos otros retinoides, no se acumula en el hígado y puede ser eficaz y al mismo tiempo relativamente no tóxico. La HPR, objeto de un estudio actualmente en curso, con su fase I concluida, en pacientes tratadas por carcinoma mamario en el Istituto Nazionali de Tumori de Milan, merece ser tenida en cuenta por los oncólogos clínicos