Effects of intravenous nutrition on tumor growth and host immunocompetence in malnourished animals.

To evaluate the effects of oral and intravenous nutritional repletion on tumor growth and host immunocompetence in malnourished animals, 60 adult purified protein derivative (PPD) positive Buffalo rats were inoculated with Morris hepatoma 5123 and were fed a regular diet for 14 days. All animals then were switched to a high carbohydrate, protein-free diet for the next 14 days, at which time only 30% of the animals remained PPD positive. Rats then were divided into three groups: group I underwent superior vena cava catheterization and received a constant infusion of 25% dextrose--4.25% amino acid solution; group II was switched to the regular protein diet orally ad libitum; and group III remained on the oral protein-free diet. PPD reactivities were measured prior to death 7 days later. Group I animals gained an average of 14 gm of body weight, and 91% of the animals were PPD positive. Group II animals lost an average of 17 gm of body weight, but 78% of the animals were PPD positive. Group III animals lost an average of 23 gm of body weight, and only 12% of the animals remained PPD positive. Absolute tumor weight and tumor weight: body weight ratios were not significantly different among the three groups of animals. Provision of adequate nutrition intravenously to malnourished tumor-bearing animals restores body weight and host immunocompetence without adversely stimulating tumor growth out of proportion to growth of the host.