Effects of alkali-metal ions on phospholipid and triglyceride synthesis in rat liver slices

R.S Leal

doi:10.1016/s0022-2275(20)39642-5

Abstract

The influence of alkali-metal ions on the incorporation of labeled precursors into phospholipids and triglycerides was studied in rat liver slices. By use of acetate-1-C14 and palmitate-1-C14 as lipid precursors, a comparison was made of the pathway from acetate to phospholipid and the pathway from palmitate to phospholipid. While the rate of incorporation of palmitate-1-C14 into phospholipids and triglyceride fatty acids was virtually independent of the alkali-metal ion present in the medium, the rate of incorporation of acetate-1-C14 into the same compounds was strongly influenced by the alkali-metal ions, the highest incorporations being obtained with potassium and rubidium. Under the same conditions lithium appears to have an inhibitory effect. The effects of the alkali-metal ions on phospholipid and triglyceride synthesis in liver are located on the pathway between acetate and long-chain fatty acids.

Highlights

In the experiments on the incorporation of albuminbound palmitate into triglyceride fatty acids, before the saponification procedure, the phospholipid-free extract was evaporated to dryness in vacuo, the residue was dissolved in petroleum ether and shaken in a separating funnel with cold aqueous 0.02 N potassium
This procedure was repeated twice and appeared to remove adequately any free palmitic acid, as tested in experiments where palmitic acid-1-C14 was added to unlabeled liver triglycerides and the triglyceride fraction tested for radioactivity
Samples of fatty acids were plated at infinite thinness on nickel planchets and weighed, and the radioactivity was measured in a 20th Century Electronics WF2 windowless gas-flowcounter with a conventionalscaler

Summary

MATERIALS AND METHODS

Adult female rats of the hooded Norwegian strain aged about 5-6 months and weighing 180-200 g were fed ad lib. on diet 41 of Bruce and Parkes [9]. Adult female rats of the hooded Norwegian strain aged about 5-6 months and weighing 180-200 g were fed ad lib. On diet 41 of Bruce and Parkes [9]. The animals were killed by cervical dislocation and the livers were rapidly removed, rinsed, and placed in ice-cold isotonic sucrose

Incubation Procedure

Specific Radioactivity

RESULTS AND DISCUSSION

Cesium min