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 se lective breeding. Blood pressure was measured in 456 adult feral baboo ns under ketamine immobilization by direct arterial cannulation. Males with blood pressures two standard deviations and females with blood p ressures one standard deviation above and below the cumulative mean we re selected as progenitors. High males were mated with high females an d low males were mated with low females. We measured blood pressure an d plasma renin activity on 100 progeny, 54 males and 46 females, great er than 44 months of age with an abbreviated tether protocol and softw are 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 fo r 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. Heritabil ity 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 r igorous measurement of blood pressure, lines of baboons with significa nt differences in blood pressure can be developed.