Regulation of plasma-free fatty acid mobilization by dietary glucose in Ehrlich ascites tumor-bearing mice

Abstract

We studied the ability of dietary glucose to cause an abrupt inhibition of free fatty acid (FFA) mobilization in mice bearing advanced Ehrlich ascites carcinoma. FFA irreversible disposal rates were estimated after i.v. injection of tracer [1-14C]palmitate complexed to mouse serum albumin. Four groups of mice were studied: 16-hr-fasted mice versus 16-hr-fasted mice refed a 58% glucose, fat-free test meal for 10 min; and control versus tumorous mice. Plasma FFA fell significantly [from 0.97 +/- 0.06 (S.E.) to 0.37 +/- 0.02 muEq/ml (n = 30 and 134, respectively)] following the ingestion of the small test meal. The lowered plasma FFA pool size remained approximately constant between t = 15 and 45 min after the mice began to eat. Tracer studies in the fasted-refed mice, carried out during that interval, showed that the plasma FFA irreversible disposal rate was reduced by 50% in both control and tumor-bearing mice. Although cancerous mice tended to have elevated plasma FFA levels in the early morning, these animals appear to have normal control mechanisms for inhibiting FFA mobilization following ingestion of carbohydrate.