Factors affecting neurotoxicity by p-bromophenylacetylurea in rats

Adult rats more than 9-10 weeks old are more susceptible to neurointoxication by p-bromophenylacetylurea than young, more actively growing rats. There is no difference in sensitivity between the sexes.

Partial hepatectomy and damaging the liver with carbon tetrachloride before administering pBPAU are procedures which enhance the degree of neurotoxicity. These studies suggest that the substance is toxic per se, and that it is probably detoxicated by the liver.

Animals treated with sodium phenobarbital both before giving pBPAU and afterwards showed a slightly increased degree of neurointoxication. Pretreatment only with sodium phenobarbital before giving pBPAU did not alter the degree of neurotoxicity. This suggests that the liver microsomal enzymes induced by phenobarbital do not play a direct role in the hepatic metabolism of pBPAU.

pBPAU is not an inhibitor of acetylcholine acetyl-hydrolase (EC No. 3.1.1.7) or benzoylcholine hydrolase (EC No. 3.1.1.9).

The proliferation of astrocytes around a needle wound in the rat brain

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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.