[Effects of oxythiamine and pyrithiamine on rat liver. --Biochemical and morphological changes in the thiamine deficient rat (author's transl)].

We studied biochemical changes in the rat liver in a thiamine (T) deficient state as induced by oxythiamine (OT), pyrithiamine (PT) and thiamine deficient diet (TDD) and simultaneously observed morphological changes under light and electron microscope. Severe loss of weight was observed in the OT treated rats fed on TDD (OTD) and such was frequently accompanied by a complete loss of righting reflex. Biochemical changes commonly found in T deficient groups were decrease in serum total protein, alkaline phosphatase activity and liver lipids, and increase in serum total cholesterol and transaminase activity. Microscopically, most of the liver cells were atrophied and necrosis was observed in the OTD group. Electron microscopically, ultrastructural changes revealed active Kupffer cells, microvilli and Golgi apparatus, and decrease in rough endoplasmic reticulum (rER) associated with increasing detached ribosomes and smooth ER. Abnormal nucleus and mitochondria were found in the OTD group. These results suggest that a T deficiency occurs readily and easily within a short time when a T antagonist, particularly OT, is used together with the TDD, while a much longer time is required to produce a T deficiency with only the TDD.