1. Physiol Genomics. 2006 Mar 13;25(1):39-49.
Genetic linkage of urinary albumin excretion in Dahl salt-sensitive rats:
influence of dietary salt and confirmation using congenic strains.
Garrett MR(1), Joe B, Yerga-Woolwine S.
Author information:
(1)Department of Physiology and Cardiovascular Genomics, Medical University of
Ohio, Toledo, Ohio 43614-5804, USA. mgarrett@meduohio.edu
Previously, we reported a linkage analysis for urinary albumin excretion (UAE)
from a backcross population derived from the Dahl salt-sensitive (S) rat and the
spontaneously hypertensive rat (SHR) raised on a low-salt diet. The present study
sought to examine the effect of salt loading on the observation of UAE
quantitative trait loci (QTL) using a F1(S x SHR) x S backcross population (n =
228) raised on a 2% NaCl diet. Parental strain data demonstrated that S rats have
significantly higher blood pressure (BP) and UAE compared with either F1(S x SHR)
or SHR at 8 wk of age, and this difference was exacerbated by 12 wk of age in
response to a high-salt diet (2% NaCl). Genome scans done at 8, 12, and 16 wk of
age yielded eight QTL for UAE. At week 8 (low salt), QTL for UAE were observed on
rat chromosomes (RNO) 1, 2, 6, 8, 9, 11, 13, and 19. Week 8 linkage analysis
confirmed previous linkage data and provided a baseline to examine the effect of
salt loading at subsequent time points. At weeks 12 and 16 (after salt- loading),
QTL for UAE were observed on RNO1, -6, -8, -9, and -13. Surprisingly, UAE QTL
were no longer observed on RNO2, -11, and -19 after salt loading, suggesting that
these QTL are attenuated by increased salt intake. The effects of UAE QTL on
RNO2, -6, -9, -11, and -13 were examined using congenic strains whereby the SHR
alleles at each QTL were placed on the S background. These congenic strains
demonstrated large and significant effects on UAE compared with the S rat,
proving that QTL for UAE reside on these chromosomes.
PMID: 16534143 [PubMed - indexed for MEDLINE]
PUBMED: 16534143
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