Premium
Renomedullary interstitial hyaluronan is important for hydration‐induced diuresis
Author(s) -
Hansell Peter,
Palm Fredrik,
Stridh Sara
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1100.1
Subject(s) - diuresis , chemistry , excretion , diuretic , endocrinology , medullary cavity , tonicity , medicine , kidney , sodium , renal medulla , tubular fluid , renal cortex , reabsorption , biochemistry , organic chemistry
Hyaluronan (HA) has been implicated in renal fluid handling due to its water attracting properties and the dynamic regulation of medullary HA levels occurring in response to variations in hydration. To directly test the importance of HA in fluid regulation, HA production was reduced by 4‐methylumbelliferone (4‐MU in drinking water for 5 days) in rats prior to acute hypotonic hydration. Following hydration for 135 min in control rats, diuresis and osmotic excretion increased while sodium excretion and GFR remained unchanged. The medullary HA content was 7.85 ± 1.29 ng/mg protein while that in the cortex was 0.08 ± 0.01 ng/mg protein. In 4‐MU‐treated rats the medullary HA content was only 38% of that in controls (p<0.05) while no change occurred in the cortex. Baseline urine flow prior to hydration was not different from controls. The diuretic response to hydration was, however, only 51% of that in the controls and the osmolar excretion was only 47%. Sodium excretion and GFR were similar to controls and remained unaltered during hydration. To conclude, reduction of renomedullary interstitial HA in rats using 4‐MU reduces the ability of the kidney to respond with an appropriate diuresis upon acute hydration. The results support our previous in vivo and in vitro data and the concept that HA is involved in fluid handling by changing the physicochemical properties of the medullary interstitium. Support: Swedish Science Council.