A low protein diet ameliorates the disrupted diurnal locomotor activity in rats after portacaval anastomosis. Steindl, Petra E., Dale L. Coy, Barry Finn, Phyllis C. Zee, and Andres T. Blei. Departments of Medicine and Neurology. Lakeside Veterans Administration Center and Northwestern University, Chicago, IL 60611
APStracts 3:0091G, 1996.
In previous studies we noted a disruption of the circadian locomotor activity rhythm in rats after portacaval anastomosis (PCA). In order to examine whether this abnormality is related to factors that aggravate hepatic encephalopathy in humans, we studied the effect of dietary formulation and protein content on body weight, locomotor activity and entrainment to the light/dark cycle in rats after PCA or sham operation. Postoperative weight loss was prevented by pair -feeding with a purified liquid diet. However, the behavioral abnormalities persisted in PCA rats fed a high protein diet, with a reduction in total activity and entrainment to the light/dark cycle. These were ameliorated by a low dietary protein content. Since this treatment reduces the load of gut-derived nitrogenous substances that might alter brain metabolism, our data strengthen the hypothesis that the abnormal circadian activity patterns in PCA rats may be part of the spectrum of hepatic encephalopathy.

Received 1 August 1995; accepted in final form 3 March 1996.
APS Manuscript Number G324-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 8 May 96