The effect of 3-methylindole on phospholipid synthesis in goat lung tissue slices

The effect of bleomycin on the uptake and incorporation of [14C]choline into phospholipids in hamster lung tissue slices

Intratracheal administration of the anticancer drug bleomycin to hamsters produced an increase in the uptake and incorporation of [14C]choline into phospholipids of lung slices in vitro. The stimulatory effect is opposite to the results obtained previously using [14C]acetate and would appear to occur distal to cytidine diphosphocholine. Although alternate explanations are possible, the results are consistent with morphological evidence, published by others, indicating an increase in lung phospholipid following bleomycin treatment, and illustrate the significance of precursor selection when evaluating the effects of xenobiotics on phospholipid synthesis.

The effect of 3-methylindole on the uptake and incorporation of 14C-choline into phospholipids in lung tissue slices

3-Methylindole (3MI) is the causative agent in the development of acute bovine pulmonary edema. Microscopic studies revealed a structural disruption in the lamellar bodies of type II cells, indicating an abnormal metabolism of phospholipid in the lung of 3MI treated animals. In the present study, lung slices from 4 goats were used to investigate the changes in phosphatidylcholine metabolism induced by 3MI. Eighteen slices were cut from each healthy lung and divided into control and 3MI groups. After a 4-hr pretreatment with 3MI (.19 or .57 mM) or carrier, the level of incorporation of 14C-choline into phosphatidylcholine, sphingomyelin and their water soluble intermediates was studied. The uptake of 14C-choline and its incorporation into phosphatidylcholine and sphingomyelin was depressed by 3MI treatment. In the water soluble fractions, the radioactivity increased in free choline and CDP-choline, while it decreased in P-choline. This suggests that choline kinase and the P-choline transferases have become relatively more rate limiting and may play a role in the depressed de novo synthesis of phosphatidylcholine induced by 3MI.