The renal circulation of conscious rabbits

1. The renal circulatory instability that some believe is inherent in rabbits was studied. 2. In five, conscious rabbits, glomerular filtration rate (GFR) averaged 4.2 +/- 0.6 ml/min/kg body wt after 1 hr, but changed to an overall average of 3.5 +/- 1.5 ml/min/kg wt after 3 hr. 3. Between-measurement coefficient of variation for GFR was more than 30% for three rabbits and 10% or less for two. 4. Renal blood flow (RBF) was even more variable. 5. The renal circulatory instability may be associated with differences in sympathetic activity by mechanisms not existing in other mammals.