Lipid metabolism, contractility, and ultrastructure of hearts of rats fed a mustard seed oil diet.

: When male weaning rats were fed a high fat-high erucic acid and diet (mustard seed oil) for 1 week, there were increases in the triglyceride and erucic acid contents in the myocardium, and an increase in the rate of incorporation of [1-14C]palmitic acid into triglyceride in the perfused heart, in comparison to rats that had consumed a high fat-high linoleic acid diet (corn oil) or a low fat diet (laboratory chow). However, continuation of the mustard seed oil diet (3-6 weeks) tended to normalize these biochemical parameters. The size of the papillary muscle isolated from the mustard seed oil-fed rats was greater than that of the muscle of the chow-fed rats, and its developed isometric tension was lower. Electron microscopic examination revealed that, in the hearts of rats having eaten the mustard seed oil diet, there were isolated foci where the number and size of mitochondria appeared to be increased.