Figure 4.

Effects of ACTH on blood pressure in mice with high (normal) and low ouabain affinity α2 Na⁺ pumps. ACTH (500 μg/kg s.c. every 8 hr × 5 days) elevated BP in wild type (WT) mice, but not in mutant mice expressing α2 Na⁺ pumps with low affinity for ouabain (α2^R/R).¹⁸ Treatment with Digibind (30 μg/kg daily, 2 hr before BP measurement), which binds ouabain with high affinity,³² but not control IgGγ, prevented the ACTH-induced elevation of BP in WT mice. ** = P < 0.1 for the pairings indicated. These re-graphed BP data were obtained by tail cuff,¹⁸ but comparable results were recently obtained by telemetry (Lingrel and colleagues, unpublished).