CARDIAC AUTOMATISM AND CHOLINE ACETYLATION IN RATS ON THIAMINE- AND PANTOTHENIC- ACID-DEFICIENT DIETS

The choline acetylating activity of extracts of the acetone powders of hearts of rats fed on diets deficient in thiamine, in pantothenate, and in thiamine plus pantothenate was found to be the same as it was in rats on a complete synthetic diet, although severe changes in the electrocardiogram (e.c.g.) were present in rats on the two thiamine-deficient diets. These e.c.g. changes were the same as the ones described in rats on diets deficient in other factors besides thiamine. The rats on the pantothenic-acid-deficient diet grew as normals did and no e.c.g. abnormalities were seen in them. The symptoms of thiamine deficiency were attenuated and their appearance delayed when pantothenate also was deleted from the diet.