Some effects of porto-caval anastomosis in the male rat.

Porto-caval anastomoses have been made on male rats which survived for up to 38 weeks. The acute phase of the consequences of this operation was associated with rapid fall in liver and body weight and a slow fall in testicular weight. Appetite also was considerably reduced and the plasma ammonium nitrogen became set at a new level of 400-500 μg./100 ml. After 12 weeks all animals were tending to gain weight, and their appetite was returning towards normal. At this phase there was an increase in both liver and testicular weight and a slow fall in plasma ammonium nitrogen. It is considered that all these features were linked and probably dependent upon the return of portal blood to the liver through adhesions around the operation site. While the plasma ammonium nitrogen levels were lowered by antibiotic treatment, they could not be further raised by dietary means.