Race, sex, and the regulation of urine osmolality: observations made during water deprivation.
Am J Physiol Regul Integr Comp Physiol
; 299(3): R977-80, 2010 Sep.
Article
em En
| MEDLINE
| ID: mdl-20573990
ABSTRACT
A more concentrated urine is excreted by blacks than whites and by men than women. The purpose of this study was to explore the physiological bases for the race and sex effects during water deprivation when osmoregulation is challenged and differences are amplified. Drinking water was withheld from 17 blacks (10 men) and 19 whites (9 men) for 24 h. Vasopressin (VP) levels and osmolality in plasma (P(osmol)) and urine (U(osmol)) were measured basally and then every 4 h. U(osmol) was higher in blacks at baseline (P = 0.01) and during water deprivation (P = 0.046). Before and during water deprivation, no differences were seen in levels of VP, P(osmol), or the VP-U(osmol) relationship between blacks and whites. Although VP levels were initially higher in men (P < 0.02 for samples collected over the first 12 h), over the last 12 h of water deprivation, U(osmol) was higher (P = 0.027) and more responsive to the level of VP (in terms of slopes, P = 0.0001) in women than men. Our results suggest that, after a period of water deprivation, there develops a sensitivity of the collecting duct to VP that is greater in women. Although U(osmol) is higher in blacks, the race difference in water conservation did not appear to result from differences in the level of VP or the sensitivity of the collecting duct to VP. Upstream effects such as Na(+) uptake in the thick ascending limb, with its ensuing effects on water reabsorption, need to be considered in future studies of the relationship of race to water conservation.
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Concentração Osmolar
/
Urina
/
Privação de Água
/
Negro ou Afro-Americano
/
Caracteres Sexuais
/
População Branca
Limite:
Adolescent
/
Adult
/
Female
/
Humans
/
Male
Idioma:
En
Revista:
Am J Physiol Regul Integr Comp Physiol
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Estados Unidos