Abstract
Impairment of autoregulation (AR) is associated with accelerated progression of chronic renal failure (CRF). As the bioavailability of insulin-like growth factor-I (IGF-I) is low in CRF, we investigated the effects of acute luminal application of 10 nM recombinant human IGF-I on AR in juxtamedullary (JM) afferent arterioles (AA) perfused in vitro with a blood solution [(approximately 30% hematocrit (HCT)]. Studies were conducted in AA from adult male rats three to four weeks after five-sixths nephrectomy (Nx) by either surgical excision (N = 7) or infarction (N = 5) of two thirds of the remnant kidney; controls (N = 6) had sham surgery. AA from both Nx groups exhibited marked hypertrophy and impaired AR responses (60 to 140 mm Hg perfusion pressure), features more pronounced in the infarction group. Responses to abluminal acetylcholine (10 microM) were similar in sham and excision groups but were significantly blunted in the infarction group. All groups vasodilated significantly after Ca-channel blockade (10 mM MnCl2). IGF-I restored AR in AA from both Nx groups (P < 0.05, analysis of variance) while it vasodilated AA from controls. These results suggest that IGF-I may protect the glomerulus from injury by maintaining autoregulatory control of renal blood flow, thereby slowing the progression of CRF.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
