Effect of Protamine Sulphate and Environmental Temperature on Mouse Sarcoma 180

Abstract

IT has been shown that protamine and its derivatives inhibit the growth of Landschutz ascites tumours and of sarcoma 180 in mice¹, and that they can retard the growth of malignant tumours in man^2,3. Protamine probably does this by inhibiting a tissue thromboplastin which is produced by malignant cells and which aids invasiveness⁴. Metabolic and pharmacological processes are influenced by changes of temperature, and so it seemed worthwhile to investigate whether these effects of protamine varied with environmental temperature. Controls given injections of physiological saline or no treatment were also included because nothing was then known about the effects of environmental temperature on tumour growth. But while this report was being written, evidence was published that more mammary tumours could be induced in rats at an ambient temperature of 32° C than at 5° C (ref. 5).