PREDICTION OF FOOD INTAKES, WEIGHT GAINS, ORGAN WEIGHTS, AND TUMOR SIZE IN TUMOR-BEARING RATS BY THE 4-PARAMETER MATHEMATICAL-MODEL FOR PHYSIOLOGICAL-RESPONSES

  • 1 January 1981
    • journal article
    • research article
    • Vol. 41  (8) , 3030-3034
Abstract
Groups of male weanling rats bearing the transplantable Novikoff [rat] ascites hepatoma were fed diets containing graded levels of protein. The food intakes and weight gains were recorded daily. Seven days after inoculation of the rats with the tumor (6 days in experiment 2), the rats were sacrificed, their organs were weighed and the tumor and ascites fluid volumes were determined. These results were analyzed by the 4-parameter mathematical model for physiological responses. Tumor-bearing rats eat and gain weight at the same rates as control rats fed identical diets, implying that this rapidly growing tumor does not interfere with the normal food intake and growth control mechanisms and the food intakes and weight gains are predictable by the 4-parameter model. Organ growth was regulated in normal and tumor-bearing rats but some actual organ weights in tumor-bearing rats were smaller than in control rats due to the presence of the tumor. Other organs (spleen, lung, kidneys and small intestine) of the tumor-bearing rats showed significant differences (P < 0.01, Student''s t test) from control rats. It was possible to predict the growth of the tumor on the basis of the casein content of the diet.