Neuroendocrine changes in Dachshunds with mitral valve prolapse examined under different study conditions

Neuroendocrine changes associated with canine mitral valve prolapse (MVP) w ere studied in 159 Dachshunds older than two years. In study 1, 102 dogs we re sampled without controlling diet or fasting period. In good accordance w ith human findings, the MVP severity correlated positively with plasma reni n activity and tended to correlate negatively with plasma aldosterone. Thes e findings were not attributable to any coexistent mitral regurgitation (MR ). In study 2, in which diet and fasting period were controlled, 57 Dachshu nds younger than seven years were sampled twice through an i.v, cannula: on ce after approximately 15 minutes in lateral recumbency and again after 10 minutes of walking. In both study 2 settings, neither MVP nor MR correlated significantly with plasma levels of renin, aldosterone, angiotensin-conver ting enzyme, norepinephrine, epinephrine, or cortisol. We conclude that the increased renin release found in early canine mitral disease is not reprod ucible under all study conditions, and that it correlates with the severity of MVP and not of MR.