ABSTRACT
ABSTRACT Considering that thiol-containing enzymes like kinases are critical for several metabolic pathways and energy homeostasis, we investigated the effects of cystine dimethyl ester and/or cysteamine administration on kinases crucial for energy metabolism in the kidney of Wistar rats. Animals were injected twice a day with 1.6 µmol/g body weight cystine dimethyl ester and/or 0.26 µmol/g body weight cysteamine from the 16th to the 20th postpartum day and euthanized after 12 hours. Pyruvate kinase, adenylate kinase, creatine kinase activities and thiol/disulfide ratio were determined. Cystine dimethyl ester administration reduced thiol/disulfide ratio and inhibited the kinases activities. Cysteamine administration increased the thiol/disulfide ratio and co-administration with cystine dimethyl ester prevented the inhibition of the enzymes. Regression between the thiol/disulfide ratio, and the kinases activities were significant. These results suggest that redox status may regulate energy metabolism in the rat kidney. If thiol-containing enzymes inhibition and oxidative stress occur in patients with cystinosis, it is possible that lysosomal cystine depletion may not be the only beneficial effect of cysteamine administration, but also its antioxidant and thiol-protector effect.
Subject(s)
Animals , Sulfhydryl Compounds , Cysteamine/pharmacology , Cystine/analogs & derivatives , Disulfides , Homeostasis/drug effects , Kidney/drug effects , Adenylate Kinase/analysis , Adenylate Kinase/drug effects , Reproducibility of Results , Rats, Wistar , Creatine Kinase/analysis , Creatine Kinase/drug effects , Cystine/pharmacology , Cystine Depleting Agents/pharmacologyABSTRACT
The treatment of cystamine, a transglutaminase (TGase) inhibitor, has beneficial effects in several diseases including CAG-expansion disorders and cataract. We compared the inhibition characteristics of cystamine with those of cysteamine, a reduced form of cystamine expected to be present inside cells. Cystamine is a more potent inhibitor for TGase than cysteamine with different kinetics pattern in a non- reducing condition. By contrast, under reducing conditions, the inhibitory effect of cystamine was comparable with that of cysteamine. However, cystamine inhibited intracellular TGase activity more strongly than cysteamine despite of cytoplasmic reducing environment, suggesting that cystamine itself inhibits in situ TGase activity by forming mixed disulfides.
Subject(s)
Humans , Cell Line, Tumor , Comparative Study , Cystamine/pharmacology , Cysteamine/pharmacology , Enzyme Inhibitors/pharmacology , Transglutaminases/antagonists & inhibitorsABSTRACT
Objetivo: El desarrollo de un sistema de maduración (MIV) y cultivo (CIV) in vitro de oocitos humanos es importante. El uso de oocitos humanos en investigación es problemático. Los oocitos de bovinos han sido propuestos como el modelo más conveniente. Se llevaron a cabo experimentos donde se evaluó el efecto que tiene la estimulación de la síntesis de glutation (GSH) durante la MIV y el CIV sobre el desarrollo embrionario y la calidad de los mismos. Materiales y Métodos: Los oocitos provenientes de ovarios de matadero fueron madurados, fertilizados, cultivados y congelados in vitro. La síntesis de glutation fue estimulada con cisteamina. La tasa de desarrollo y calidad de los embriones se estudió en 5 grupos: MIV y CIV (Día 2, embriones de 2 a 6 células) sin suplementación de cisteamina (Cist) (Grupo Control) (A); MIV suplementado con 100 mM de Cist (MIV-100) y el CIV sin suplementación (B); MIV-100 y CIV suplementado con 25 µM de Cist (C); o 50 µM de Cist (D); o con 100 µM de Cist (E). Se realizaron 7 réplicas con 1.374 oocitos. Los datos transformados se analizaron mediante ANOVA y test de Tukey. Resultados: El desarrollo de los embriones en los grupos B, C y D fueron significativamente superiores al grupo control (A). El grupo D fue el mejor (P<0.05). Además, el grupo D presentó los mejores resultados de sobrevida y eclosión embrionaria luego del congelamiento, comparado con el grupo A. Discusión: Los resultados demuestran que la estimulación de la síntesis de GSH durante la MIV y el CIV de oocitos bovinos mejora las tasas de desarrollo de los embriones y su calidad. Estos resultados nos muestran el papel preponderante que cumple el metabolismo del GSH durante la maduración citoplasmática y el desarrollo de los embriones
Subject(s)
Animals , Fertilization in Vitro/methods , Glutathione/therapeutic use , In Vitro Techniques , Antioxidants/therapeutic use , Cell Culture Techniques , Culture Media/chemistry , Cysteamine/pharmacology , Cysteamine/therapeutic use , Cystine/therapeutic use , Disease Models, Animal , Glutathione/therapeutic useABSTRACT
To determine whether exocrine pancreatic secretion is regulated by endogenous somatostatin, somatostatin deficiency was induced by cysteamine. Rats were subcutaneously administered a single dose of cysteamine (30 mg/100 g body weight) 12 hr before experiment. Anesthetized rats were prepared with cannulation into bile duct, pancreatic duct, duodenum, and jugular vein and pancreatic juice was collected. For in vitro study, isolated pancreata of rats, pretreated with cysteamine, were perfused with an intraarterial infusion of Krebs-Henseleit solution (37 degrees C) at 1.2 mL/min, and pancreatic juice was collected in 15-min samples. In vivo experiment of the rat, the mean basal pancreatic secretions, including volume, bicarbonate, and protein output were significantly increased from 18.4+/-0.5 microL/30 min, 0.58+/-0.05 microEq/30 min, and 214.0+/-26.1 microg/30 min to 51.6+/-3.7 microL/30 min, 1.52+/-0.11 microEq/30 min, and 569.8+/-128.9 microg/30 min, respectively (p<0.05). In the isolated perfused pancreas, cysteamine also resulted in a significant increase in basal pancreatic secretion (p<0.05). Simultaneous intraarterial infusion of octreotide (10 pmol/hr) to isolated pancreata partially reversed the effect of cysteamine on basal pancreatic secretion. These findings suggest that endogenous somatostatin play an important role on the regulation of basal pancreatic exocrine secretion.
Subject(s)
Male , Rats , Animals , Cysteamine/pharmacology , Hormone Antagonists/pharmacology , Hormones/pharmacology , In Vitro Techniques , Octreotide/pharmacology , Pancreas/metabolism , Pancreas/drug effects , Perfusion , Rats, Sprague-Dawley , Somatostatin/antagonists & inhibitorsABSTRACT
Se estudió en ratas Wistar el factor ácido, el mecanismo dopaminérgico periférico y el rol de las GB en la prevención o agravación de la UDC. Se halló que Bromocriptina, un agonista dopaminérgico DA2, actuó en la prevención de la UDC y en la depleción PAS de las GB. En cambio, las drogas antidopaminérgicas periféricas SCH 23390, Domperidona y SAM e agravaron la UDC y ni impidieron la depleción PAS de las GB. El efecto antidopaminérgico de Cisteamina mas SAME provocaron siempre úlceras duodenales perforadas y que fue totalmente impedido por al ligaudra del píloro. En conclusión, se postuló al factor ácido, al mecanismo dopaminérgico periférico y a las GB en la patogenia de la UDC