Lipid metabolism in the potassium deficient rat

Abstract

1. In male Wistar rats a potassium deficiency was induced be feeding up to 8 days a synthetic diet with low potassium content 10% of which consisted of sodium polystyrensulfate. 2. At the end of the period serum potassium was regularly reduced from a control level of 4.0–4.2 to 2.0–2.4 mEq./l. Total body potassium decreased by 40%. 3. Body weight remained constant or decreased by 5–10%, whereas control rats showed an increase of 10%. 4. Respiratory quotients fell from 0.89 to 0.71 and rose again when the rats were provided with potassium for 2 weeks. 5. In potassium deficient rats total body lipids decreased by about 30–40% while the nitrogen content remained constant. 6. Serum levels of total lipids, phospholipids, and total glycerol decreased by about 30–40% during potassium deficiency and became normal after repletion of potassium. 7. Serum free fatty acid levels were elevated on days 1, 2, 4, and 6 of potassium depletion. Free glycerol in the serum increased after 1 week of potassium deficiency and fell after 2 weeks following potassium repletion. 8. It can be concluded that the potassium deficient rats used predominantly fat as a substrate of oxidative metabolism. This phenomenon may be related to the known impairment of carbohydrate tolerance in this state.