Lipid metabolism in cancer cachexia

Abstract

The effect of cancer cachexia on the oxidative metabolism of lipids has been studied in mice transplanted either with the MAC 16 adenocarcinoma, which induces profound loss of host body weight and depletion of lipid stores, or the MAC 13 adenocarcinoma, which is of the same histological type, but which grows without an effect on host body weight or lipid stores. While oxidation of D-[U14C]glucose did not differ between animals bearing tumours of either type and non-tumour bearing controls, oxidation of [l14C]triolein administered by intragastric intubation was significantly (P<0.05) higher in animals bearing the MAC 16 tumour than in either non tumour-bearing controls or in animals bearing the MAC 13 tumour. Intestinal absorption of [14C]lipid was significantly (P<0.05) reduced in animals bearing the MAC 13 tumour when compared with either non tumour-bearing animals or MAC 16 tumour-bearing animals, but was not significantly different in the latter two groups. The level of labelled lipids in heart and adipose tissue after an oral [14C]lipid load was significantly lower in animals bearing the MAC 16 tumour compared with the other two groups. The level of tumour lipids was also higher in the MAC 16 than in the MAC 13 tumour after both an oral [4C]lipid load or by direct injection of [U4C]palmitate complexed to albumin into epididymal fat pads. Oxidation of [U14C]palmitate was also significantly enhanced in liver and heart homogenates from animals bearing the MAC 16 tumour. These results suggest that in cachectic tumour-bearing animals mobilisation of body lipids is accompanied by an increased utilisation. © 1992 Macmillan Press Ltd.