STIMULATION OF TUMOR-GROWTH IN ADULT-RATS INVIVO DURING ACUTE STREPTOZOTOCIN-INDUCED DIABETES

  • 1 April 1987
    • journal article
    • research article
    • Vol. 47  (7) , 1756-1761
Abstract
The effects of acute diabetes mellitus on the growth of Morris hepatoma 7288CTC and Jensen sarcoma were studied in fed, young (less than 200 g), and adult (greater than 250 g) rat. Animals were matched for tumor site and growth; the rate of tumor growth were the same in fed, young and adult nondiabetic rats. Diabetes was induced by the i.v. injection of streptozotocin (65 mg/kg total body weight) into tumor-bearing rats and changes in arterial blood nutrient concentrations were compared to changes in the rates of tumor growth and DNA synthesis. In young rats acute diabetes did not increase the blood concentrations of the fat store-derived nutrients and did not increase the rate of tumor growth. In adult rats, however, acute diabetes raised the arterial blood free fatty acid, glycerol, triglyceride, and ketone body concentrations to high levels and increased the rate of tumor growth about three times over the observed in untreated rats. Progress values for the mobilization of host fat stores and for incorporation of [methyl-3H]thymidine into tumor DNA during the onset of diabetes showed that these activities were closely related in adult rats. Both proceses began to increase 2 to 4 h after streptozotocin treatment, reached an initial peak at 12 to 16 h, decreased to a low point at 18 to 20 h, had then increased again to the new steady state after 23 to 24 h. The results indicate that the rate of tumor growth of rats in vivo is limited by the availability of a substance(s) present in the hyperlipinic blood of adult diabetic rats. The tight relationship between host lipolysis and tumor growth suggest that the substance(s) is dried from host fat stores.

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