Selective breeding to develop lines of baboons with high and low blood pressure

Lines of baboons with high and low blood pressure were developed by selective breeding. Blood pressure was measured in 456 adult feral baboons under ketamine immobilization by direct arterial cannulation. Males with blood pressures two standard deviations and females with blood pressures one standard deviation above and below the cumulative mean were selected as progenitors. High males were mated with high females and low males were mated with low females. We measured blood pressure and plasma renin activity on 100 progeny, 54 males and 46 females, greater than 44 months of age with an abbreviated tether protocol and software program for data collection. Mean systolic and diastolic nighttime pressures for the high line were 126/72 and for the low line were 114/65 mm Hg. Line differences for systolic (12 mm Hg) and for diastolic (7 mm Hg) pressures were significant (p < 0.001). The line difference for plasma renin activity (1.1 [ng/mL]/hr) was not significant. Progeny pressures ranged from 84/49 to 191/126 mm Hg. There was no sex effect on blood pressure or plasma renin activity line differences. Heritability of systolic pressure was 0.46 +/- 0.19 and of diastolic pressure was 0.32 +/- 0.19. These results indicate that, by selective breeding and rigorous measurement of blood pressure, lines of baboons with significant difference in blood pressure can be developed.