Abstract
The activity of α-keto acid dehydrogenases ; pyruvate dehydrogenase and 2-oxoglutarate dehydrogenase in liver mitochondria of thiamine-deficient, normal and thiamine-loading rats was estimated by the spectrophotometric method using ferricyanide as electron acceptor. The activity of α-keto acid dehydrogenases decreased significantly in thiamine-deficient rats, but by the addition of thiamine diphosphate in vitro, the activity was fairly elevated though not complete. Single intraperitoneal injection of thiamine (2mg) to deficient rats restored rapidly the activity to the extent of the normal rats. No change of the α-keto acid dehydrogenases'activity was observed in rats 4 hours after single intraperitoneal injection of thiamine (4mg). These suggest that there has been no effect of α-keto acid dehydrogenase activity with a large dose administration of thiamine. However, in the rats administered daily thiamine (2mg) for 8 days, pyruvate dehydrogenase activity showed a tendency of increase by addition of thiamine diphosphate, in vitro.
