Lipogenesis in tumour and host tissues in mice bearing colonic adenocarcinomas.

Although animals bearing the MAC16 colon adenocarcinoma showed progressive weight loss, the average food consumption (15.1 +/- 0.6 Kcal day-1) did not differ from non tumour-bearing controls (15.3 +/- 0.3 Kcal day-1), while animals bearing a related colon adenocarcinoma, MAC13, which had no effect on body weight had a significantly (P less than 0.01) elevated food intake (16.4 +/- 0.3 Kcal day-1) above controls. Weight loss in animals bearing the MAC16 tumour was associated with a significant reduction in the percentage contribution of the kidneys, colon and epididymal fat pads to the total body weight. Although loss of body fat occurred only in the MAC16 model, both tumours were capable of synthesising lipids from glucose both in vitro and in vivo at the same rate. In addition both tumours increased the rate of lipogenesis from glucose in kidney, liver and epididymal fat pads of the host. Lipogenesis from glucose would be expected to result in a loss of utilisable carbohydrate energy and thus would be expected to increase the overall energy requirements in the tumour-bearing state leading to catabolism of host body tissues if the energy intake is not increased.