In vivo inhibition of Walker 256 tumour carnitine palmitoyltransferase I by soya oil dietary supplementation.

The role of dietary fatty acids in the regulation of carnitine palmitoyltransferase (CPT) activity has been shown in liver but their role in the regulation of tumour CPT activity in vivo is unknown. The present study investigated the effects of several oils, given as dietary supplements, upon the activity of CPT I and II in the Walker 256 rat tumour and the inhibition or stimulation of tumour growth. CPT I activity was markedly inhibited by soya oil, rich in linoleic acid (70% inhibition vs control). CPT I mRNA expression was not inhibited by any of the oils studied, indeed soya oil caused a marked increase (132% vs control) in expression. These results suggest that soya oil can modulate, in vivo, the beta-oxidative pathway of tumour tissue and further supports the hypothesis of tumour CPT I regulation by polyunsaturated fatty acids.