RESUMEN
In vitro studies have shown that multidrug resistance protein 1 (MDR1) has an affinity for cortisol; however, in vivo association studies on the relationship between MDR1 gene polymorphisms and blood cortisol levels have produced inconsistent results. Therefore, we examined the effects of the C3435T polymorphism of the MDR1 gene on blood levels of hypothalamus-pituitary-adrenal (HPA) axis hormones such as cortisol and adrenocorticotropic hormone (ACTH) in healthy subjects. The subjects comprised 30 healthy Japanese males. Ten subjects were recruited for each of the C3435T MDR1 genotypes: C/C, C/T, and T/T. Blood samples were taken at 6:00 pm on two occasions with an interval of 2 weeks. Blood levels of cortisol and ACTH were determined by an electrochemiluminescence immunoassay. There were no significant differences in the blood levels of the HPA axis hormones among the MDR1 genotypes. The present study suggests that the C3435T MDR1 polymorphism does not affect blood levels of HPA axis hormones in healthy Japanese males.
Asunto(s)
Sistema Hipotálamo-Hipofisario/metabolismo , Sistema Hipófiso-Suprarrenal/metabolismo , Subfamilia B de Transportador de Casetes de Unión a ATP/genética , Subfamilia B de Transportador de Casetes de Unión a ATP/metabolismo , Hormona Adrenocorticotrópica/sangre , Adulto , Alelos , Frecuencia de los Genes , Genotipo , Voluntarios Sanos , Humanos , Hidrocortisona/sangre , Japón , Masculino , Polimorfismo de Nucleótido SimpleRESUMEN
BACKGROUND: Subclinical alterations of small intestinal function have been reported frequently in tropical countries. Studies of small intestinal permeability to lactulose and mannitol were therefore completed in Guatemalan infants from a low-income, periurban community to assess the prevalence of altered intestinal function and the factors associated with this condition. METHODS: Two hundred studies were successfully completed in 158 infants who had been free of diarrhea for at least 1 week before the day of study. Urinary concentrations of lactulose and mannitol during the 5-hour period after ingestion of 400 mg/kg body weight of lactulose and 100 mg/kg body weight of mannitol were measured by gas-liquid chromatography and compared by age group, feeding practices, anthropometric indexes, and serum iron and zinc concentrations. RESULTS: The overall prevalence of altered intestinal permeability (defined as a ratio of urinary recovery of lactulose to mannitol [L/M] > or =0.07) was 30%. The urinary L/M recovery ratio was positively associated with age; low weight for age; and, in infants less than 6 months of age, non-breast-feeding. Children with serum iron concentrations less than 7.16 microM/l (40 [microg/dl) had higher median L/M ratios (L/M = 0.068; 95% confidence interval [CI], 0.054, 0.085) than those with iron levels higher than this cutoff (L/M = 0.052; CI = 0.046, 0.058; p = 0.038). The median urinary L/M recovery ratio in 10 currently asymptomatic infants who had diarrhea during the week before testing (0.087; CI = 0.49, 0.154) was higher than that in children who had been free from diarrhea for at least 1 week (0.052; CI = 0.048, 0.056; p = 0.01). CONCLUSION: Age, feeding practices, low weight-for-age, low serum iron concentration, and recent diarrhea were all associated with altered intestinal function in this group of Guatemalan infants.