Characterization of the Adrenal 11β-Hydroxylase in Inbred Salt-Sensitive and Resistant Rats

Rats have been bred for susceptibility and resistance to the hypertensive effect of dietary salt (S/JR & R/JR). S/JR have an abnormal adrenal steroid 11β,18-hydroxylase activity resulting in increased production of 18-OH-DOC. S/JR also produce increased quantities of 19-nor-DOC, which may be related, since the 11β,18-hydroxylase also catalyzes the 19-hydroxylation of DOC, a pivotal step in 19-nor-DOC biosynthesis. The purpose of the present studies was to further characterize the mutant S/JR adrenal steroid 11β,18-hydroxylase. Preliminary studies are also presented on assessing the renal 19-desmolase, the last step in 19-nor-DOC biosynthesis. Adrenal glands were harvested from R/JR and S/JR and prepared for incubation studies, protein immunoblotting, and RNA analysis. Kidneys from Sprague-Dawley rats were also used for isolated renal perfusion studies.Both S/JR and R/JR strains had a single immunostaining band for 11β,18-hydroxylase at 51,000 molecular weight which were equal in intensity. Both strains ha...