Differential Effect of Salt Loading on Sodium and Lithium Excretion in Dahl Salt‐Resistant and ‐Sensitive Rats
作者:
JAN ROOS,
KENT KIRCHNER,
JOHN ABERNETHY,
HERBERT LANGFORD,
期刊:
Hypertension
(OVID Available online 1984)
卷期:
Volume 6,
issue 3
页码: 420-424
ISSN:0194-911X
年代: 1984
出版商: OVID
关键词: fractional lithium excretion;Dahl rats;volume expansion;renal sodium handling
数据来源: OVID
摘要:
Fractional excretion of lithium, as a marker for proximal sodium reabsorption, was determined in normotensive Dahl S rats (susceptible to NaCI hypertension) and Dahl R rats (resistant to NaCI hypertension) before and following an acute sodium load. Baseline mean arterial pressures, inulin clearances, sodium excretion rates, and fractional lithium clearances were not different between the R and S rats. Following the salt loading and despite similar mean arterial pressures and degree of volume expansion, the glomerular filtration rate, urinary flow rates, and absolute sodium excretion rates were greater in R than S rats. The fractional excretion of lithium was also greater in R than S rats. These data demonstrate that, at equal mean arterial pressures, Dahl S rats have a reduced capacity for sodium excretion, and that this defect is present prior to the development of hypertension. Furthermore, the observation that these animals also have a lower fractional lithium excretion during volume expansion suggests that salt loading reduces proximal tubule reabsorption to a lesser extent in Dahl S than R rats. These data suggest that the subnormal sodium and water excretion observed after sodium loading in S rats may be partially due to an abnormality in proximal tubule sodium handling.
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