Asunto(s)
Núcleo Celular/efectos de los fármacos , Aberraciones Cromosómicas , Gosipol/farmacología , Espermátides/efectos de los fármacos , Espermatogénesis/efectos de los fármacos , Animales , Núcleo Celular/ultraestructura , Masculino , Meiosis/efectos de los fármacos , Ratas , Ratas Endogámicas , Espermátides/ultraestructura , Factores de TiempoRESUMEN
The clastogenic and mutagenic activities of a new antifertility and antitumor agent gossypol were studied in the mouse male germ cells. Results of the present work indicate that at the doses 125 and 250 mg/kg the drug does not significantly increase frequencies of the micronuclei in the early spermatids and sperm head abnormalities. Hence, genotoxic influence can not be proposed as responsible for the antifertility effect of gossypol.
Asunto(s)
Gosipol/toxicidad , Mutágenos , Espermátides/efectos de los fármacos , Espermatozoides/efectos de los fármacos , Animales , Núcleo Celular/efectos de los fármacos , Núcleo Celular/ultraestructura , Masculino , Ratones , Cabeza del Espermatozoide/efectos de los fármacos , Cabeza del Espermatozoide/ultraestructura , Espermátides/ultraestructura , Espermatozoides/ultraestructuraRESUMEN
The vitamin A effects on cell proliferation, differentiation and functioning might be due to its influence on genome expression at the level of regulation of the transcription of certain genes, posttranscriptional modification of mRNA levels, or changes in the membrane structural-functional organization. Vitamin A can affect the biosynthesis of various proteins, including those involved in regulation of development and cell functioning or determining cell sensitivity to hormones and hormone-like factors. Vitamin A can also influence the formation of secretory proteins which play the role of hormones. It is proposed to use the differential sensitivity of various cells in cell populations to vitamin A or its forms for studying intercellular relations. In particular, the capacity of retinol and retinoic acid to maintain the development and functioning of various vitamin A-dependent cells of the testis can be used for studying local regulation of spermatogenesis in mammals.
Asunto(s)
Células/efectos de los fármacos , Vitamina A/farmacología , Animales , Diferenciación Celular/efectos de los fármacos , División Celular/efectos de los fármacos , Fenómenos Fisiológicos Celulares , Regulación de la Expresión Génica/efectos de los fármacos , Masculino , Biosíntesis de Proteínas , Espermatogénesis/efectos de los fármacos , Transcripción Genética/efectos de los fármacos , Vitamina A/metabolismoAsunto(s)
ADN/análisis , Histonas/análisis , Enfermedades de las Ovejas/metabolismo , Espermatozoides/análisis , Deficiencia de Vitamina A/veterinaria , Animales , Cromatina/análisis , Citofotometría , Masculino , Ovinos , Vitamina A/administración & dosificación , Vitamina A/sangre , Deficiencia de Vitamina A/metabolismoRESUMEN
It has been shown that in rats with alimentary hypovitaminosis A, with a sufficiently pronounced decrease in the content of free retinol in blood serum (below 140 ng/ml) and in the liver tissue (below 360 ng/g), there is a complete regression of Pliss's lymphosarcoma. Under the conditions indicated, retinoic acid, in contradistinction to retinol, does not promote the tumor growth. A relative and absolute reduction in blood plasma of the essential amino acids, arginine, methionine and lysine, might be one of the reasons for tumor regression under hypovitaminosis A.
Asunto(s)
Linfoma no Hodgkin/patología , Deficiencia de Vitamina A/patología , Animales , Diterpenos , Hígado/metabolismo , Linfoma no Hodgkin/metabolismo , Masculino , Trasplante de Neoplasias , Ratas , Ratas Endogámicas , Ésteres de Retinilo , Vitamina A/análogos & derivados , Vitamina A/metabolismo , Deficiencia de Vitamina A/metabolismoRESUMEN
Dynamics of vitamin A turnover in the blood and semen of astrakhan ram-sires was being studied for determining the ways of its transport to mature sperms. By means of high pressure liquid chromatography it was found that concentrations of retinol in the blood and retinyl palmitate in the semen of rams, suffering from hypovitaminosis A, rose simultaneously during the first 24 hours after feeding the animals with labelled retinol. According to the data on the specific activity of labelled vitamin A in the blood and semen a significant portion of the vitamin was transfered into the semen from the blood together with the secretions of epididymis and/or another sexual glands. The role of vitamin A in epididymal sperm maturation is discussed. A more prolonged increase of vitamin A levels in the blood and semen of the animals under study was achieved after double feeding of each animal with 60 mg of vitamin A.
Asunto(s)
Semen/metabolismo , Ovinos/metabolismo , Vitamina A/metabolismo , Alimentación Animal , Animales , Inseminación Artificial/veterinaria , Masculino , Retinaldehído/administración & dosificación , Semen/análisis , Espermatogénesis , Espermatozoides/análisis , Espermatozoides/metabolismo , Vitamina A/análisisRESUMEN
Retinol deficiency in rats was shown to cause atypical changes of DNP-complex in spermatogenic cells and a decrease in their fertility. The final stages of spermiogenesis were found to be the most sensitive: ca. 25% of testicular sperms were characterized by abnormal chromatin structure and deficiency in spermiospecific argininerich histones what might be related to a sharp decrease in arginine content in blood plasma. Similar results were obtained with rats kept on retinoic acid. Thus, retinoic acid fails to restore retinol-dependent processes involved in the formation of sperms with normal DNP-complex.
Asunto(s)
Desoxirribonucleoproteínas/metabolismo , Espermatogénesis , Espermatogonias/metabolismo , Espermatozoides/metabolismo , Deficiencia de Vitamina A/metabolismo , Animales , Diferenciación Celular , ADN/metabolismo , Diterpenos , Fertilidad , Histonas/metabolismo , Masculino , Ratas , Ratas Endogámicas , Ésteres de Retinilo , Espermatogonias/citología , Factores de Tiempo , Tretinoina/administración & dosificación , Tretinoina/análogos & derivados , Vitamina A/administración & dosificación , Vitamina A/análogos & derivados , Vitamina A/metabolismoRESUMEN
Enzymic hydrolysis of retinyl phosphate in subcellular fractions of the rat liver has been investigated. A quantitative method of measuring activity of retinyl phosphatase has been developed. The method is based on the isolation of labeled retinol, the substance formed from chemically synthesized labeled retinyl phosphate through enzymatic hydrolysis. It has been shown that the major quantity of retinyl phosphatase activity (75%) with a specific activity of 80 micrograms retinyl phosphate hydrolyzed for 30 min/mg protein at 30 degrees C occurs in plasmatic membranes.
Asunto(s)
Hígado/enzimología , Monoéster Fosfórico Hidrolasas/análisis , Animales , Membrana Celular/enzimología , Núcleo Celular/enzimología , Femenino , Masculino , Ratones , Fosfatos de Poliisoprenilo , Fracciones Subcelulares/enzimología , Vitamina A/análogos & derivadosRESUMEN
Retinyl phosphate (RP) has been synthesized from retinol (R), using phosphodimorpholine chloride (PDMC) or POCl3. A method for isolating and purifying RP from the reaction mixture has been developed. The RP yield varies from 3 to 6% depending on the quantities of R and POCl3. The RP yield can be increased by 10--15% as a result of RP separation and rerun of the reaction. The resultant RP has an absorption maximum at 325 nm, is described by the formula C20H27PO4(NH4)2 and distributed between equal volumes of diethyl ester and 20% aqueous methanol at a ratio of 1:1. RP is alkaline-resistant and rapidly transforms into anhydroretinol (AR) in the acid medium. Eighteen hours after RP administration into the caudal vein or parenterally retinyl palmitate and R are accumulated in the liver of A-avitaminous rats.