Colchicine improves the alterations in the liver adenylate cyclase system of cirrhotic rats.

ABSTRACT

The adenylate cyclase system and the number and affinities of receptors for insulin and glucagon were studied in rats treated with CCl4 and in rats that received colchicine in addition to CCl4. Liver glycogen, cAMP and total collagen content were also measured in those animals. Rats received only mineral oil or only colchicine were used as controls. In this latter group, all parameters measured were normal. Differences in liver collagen content between groups treated with CCl4 and CCl4 + colchicine were not statistically significant. Basal adenylate cyclase activity was 2-fold increased in the CCl4 group. In the animals receiving CCl4 and colchicine, adenylate cyclase activity was normal. Adenylate cyclase activity stimulated by fluoride or by glucagon was also increased in the CCl4 group. However, this increase was due to to the enhanced basal activity. The number of receptors and the affinities of the receptors of glucagon and insulin were normal in all groups. cAMP levels were found increased in the CCl4 treated animals and this was accompanied by a 90% reduction in liver glycogen. In the group treated with CCl4 + colchicine, cAMP was normal and liver glycogen was only reduced 25%. These results suggest that part of the clinical and biochemical improvements observed in the colchicine treated animals were due in part to a reversal of the alterations of the adenylate cyclase system induced by CCl4.