The Effect of Ethionine on the Energy Producing Metabolism in the Rat Pancreas - I. The Influence on the Activities of Key Enzymes of Various Matabolic Pathways
1. The effect of daily intraperitoneal injections of either 0.25 mg or 0.5 mg d,l-ethionine per gram body weight on the activities of several key enzymes in the energy-producing metabolism of the pancreas was studied in female rats over a period of one to ten days. 2. 0.25 mg/gm induced a significant but transient increase in the activities of phosphofructokinase (F-6-PK), glycerophosphate dehydrogenase (GDH), and condensing enzyme (CE). A smaller increase was seen in the case of hexokinase (HK), glucose-6-phosphate dehydrogenase (G-6PDH) and NAD-dependent isocitrate dehydrogenase (NAD-IDH). No change in glyceraldehyde phosphate dehydrogenase (GAPDH), hydroxyacyl CoA dehydrogenase (HOAD), or NADP-dependent isocitrate dehydrogenase (NADP-IDH) was observed. Thus the elevation affected mainly the rate-limiting enzymes in the metabolic pathways (F-6PK, GDH, CE, HK). 3. The higher dosage of 0.5 mg/gm b.w. resulted in very marked reductions of all enzyme activities measured, except for F-6PK and HK, which showed a transient increase on the first day. 4. The increase in enzyme activity could be a short term adaptation to the decreased tissue levels of ATP induced by ethionine. 1 This research work was supported by the Deutsche Forschungsgemeinschaft, grant GO 118/7