Aging and salt-loading modulate blood pressure QTLs in rats.
To evaluate the effects of nongenetic factors, aging, and salt-loading on the quantitative trait loci (QTLs) for blood pressure (BP), we conducted a genome-wide linkage analysis using multiple sets of BP measurements in 125 male F2 generation cross derived from stroke-prone spontaneously hypertensive rats and normotensive Wistar-Kyoto rats. The experiment was arranged in two stages. In the first stage, corresponding to the developing period of the rats, BP was measured repeatedly without loading of salt; this continued until the rats were 5 months of age. In the second stage, after the baseline BP leveled off, 1% salt water was given to the rats and BP was monitored for the subsequent 7 months. Genome scanning was performed using 201 markers. In the developing period, three QTLs were identified on chromosomes 1, 3, and 4 (logarithmic odds [LOD] scores of 5.6, 3.1, and 3.2, respectively), which had peaks at 8 or 10 weeks of age. In the latter salt-loading stage, QTLs for BP were detected on chromosomes 1 and 10 (LOD scores 4.6 and 4.5, respectively). When the BP increase during salt-loading was analyzed as a phenotype, however, only the region on chromosome 10 showed linkage at a suggestive level (LOD score 3.2). The present study provides experimental evidence that QTLs for BP could be modulated by nongenetic factors, such as aging and salt-loading.
Mashimo
T
T
Department of Life Science, Graduate School of Human and Environmental Studies, Kyoto University, Japan.
Nabika
T
T
Matsumoto
C
C
Tamada
T
T
Ueno
K
K
Sawamura
M
M
Ikeda
K
K
Kato
N
N
Nara
Y
Y
Yamori
Y
Y
D000375:Aging; D000818:Animals; D001794:Blood Pressure; D002874:Chromosome Mapping; D002875:Chromosomes / Q000235:genetics; D004247:DNA / Q000032:analysis; D005260:Female; D008040:Genetic Linkage; D006973:Hypertension / Q000097:blood / Q000235:genetics*; D008297:Male; D016133:Polymerase Chain Reaction; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012965:Sodium Chloride / Q000008:administration & dosage*
D012965:Sodium Chloride; D004247:DNA