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Normal renal autoregulation in the presence of diabetic hyperfiltration
Author(s) -
Cupples William,
Lau Catherine
Publication year - 2008
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.22.1_supplement.944.10
Subject(s) - autoregulation , tubuloglomerular feedback , medicine , renal function , endocrinology , renal blood flow , afferent arterioles , blood pressure , angiotensin ii
In uncomplicated type 1 diabetes mellitus (DM1) glomerular filtration (GFR) is often elevated despite normal renal blood flow (RBF). This diabetic hyperfiltration, and the accompanying salt paradox, in which GFR is inversely related to salt intake, result from afferent vasodilatation mediated by tubuloglomerular feedback (TGF). TGF normally contributes to autoregulation directly and by modulation of the myogenic mechanism. Therefore we tested renal autoregulation in rats with early (4 weeks) and longer term (12 weeks) DM1. Diabetic hyperfiltration (inulin clearance) was present in early DM1 in rats receiving normal salt intake, but not in those receiving high salt intake (∼4x chow), thus confirming the salt paradox. In early DM1, RBF dynamics were not different either between control and DM1 rats, or between control or DM1 rats receiving normal or high salt intake. At 12 weeks DM1, RBF dynamics were still not different from control. In addition the steady‐state pressure‐flow relationship showed significantly enhanced autoregulation at 50 – 80 mmHg in DM1 rats on normal salt compared with all other groups which did not differ. The results demonstrate effective autoregulation of RBF in DM1 that is identical to controls and they suggest that TGF‐mediated hyperfiltration (salt paradox) in early DM1 does not compromise autoregulation. Funded by HSFBCY