COSEGREGATION OF SPONTANEOUSLY HYPERTENSIVE RAT RENIN GENE WITH ELEVATED BLOOD-PRESSURE IN AN F-2 GENERATION

Objective. To investigate the role of the renin gene in the hypertensi on of the spontaneously hypertensive rat (SHR) of the Okamoto strain. Methods. We determined whether the SHR renin allele was cosegregated w ith high blood pressure in 137 F-2 rats derived from inbred SHR and Wi star-Kyoto rats. Systolic blood pressure in conscious rats was measure d by the tail-cuff method, whereas mean arterial pressure was determin ed from an indwelling catheter in the left carotid artery. Renin genot ypes of F-2 rats were determined using a SHR-specific Bg/II restrictio n fragment length polymorphism that we have previously described. Resu lts. The SHR renin allele was cosegregated significantly with higher s ystolic blood pressure in male F-2 rats aged 8-24 weeks and in females aged 12-24 weeks, The greatest differences in blood pressure between SHR renin allele homozygotes and Wistar-Kyoto rat renin allele homozyg otes were 35 mmHg for males and 17 mmHg for females aged 24 weeks. The SHR renin allele was also associated with a higher mean arterial pres sure in rats aged 24 weeks and cosegregated with higher body weight of male F-2 rats aged 12-24 weeks but not with that of the females. In c ontrast to the relationship with blood pressure, the SHR renin allele was segregated with lower plasma renin concentrations in rats aged 24 weeks. Conclusion. These results are consistent with the SHR renin gen e being one of the loci determining high blood pressure in rats of thi s strain, possibly through action at some extra-renal site subserving control of blood pressure. J Hypertens 16:1141-1147. (C) 1998 Lippinco tt-Raven Publishers.