Dietary fat modifies some metabolic actions of human recombinant tumour necrosis factor alpha in rats

To examine how fat might influence the metabolic effects of tumour necrosis factor alpha (TNF alpha), human recombinant TNF alpha was given intravenously to rats that had been fed for 12 weeks on diets containing (g/kg) 200 maize oil or 190 coconut oil + 10 maize oil. Rectal temperature and tissue composition measurements were made 8 and 24 h after injection. Ambient temperatures of 20 degrees and 25 degrees were employed to accentuate rectal temperature changes. Doses of 30 and 300 micrograms TNF alpha/kg body-weight were given, and brought about depression of serum zinc and albumin and elevation of copper. Muscle protein content was decreased and liver protein and Zn content enhanced by TNF alpha. Serum Zn and liver Zn content were negatively correlated 8 h after injections. Hypothermia developed within 1 h of injection. All responses except the rise in serum Cu and gain in liver Zn were more intense at the higher than at the lower dose of TNF alpha. Hypothermia was exacerbated by an environmental temperature of 20 degrees. The coconut-oil diet blunted the hypothermia and likewise the changes in serum albumin and Cu content 8 h after injections and in muscle and liver protein after 24 h. Changes in eicosanoid metabolism may be involved in the modulatory effects of the coconut-oil-enriched diet.